Multi-pole synchronous pulmonary artery radiofrequency ablation catheter

ABSTRACT

A multi-pole synchronous pulmonary artery radiofrequency ablation catheter may comprise a control handle, a catheter body and an annular ring. One end of the catheter body may be flexible, and the flexible end of the catheter body may be connected to the annular ring. The other end of the catheter body may be connected to the control handle. A shape memory wire may be arranged in the annular ring. One end of the shape memory wire may extend to an end of the annular ring and the other end of the shape memory wire may pass through a root of the annular ring and be fixed on the flexible end of the catheter body. The annular ring may be provided with an electrode group. The device possesses advantages of simple operation, short operation time and controllable precise ablation. The device can be used to treat pulmonary hypertension with pulmonary denervation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Application No.62/023,781 filed on Jul. 11, 2014, the entire contents of which ishereby incorporated by reference. This application is also acontinuation-in-part application of U.S. application Ser. No. 14/530,588filed on Oct. 31, 2014, and U.S. application Ser. No. 14/079,230 filedon Nov. 13, 2013, which claims priority to Chinese Application No.201210453470.4 filed on Nov. 13, 2012, and Chinese Application No.201310103141.1 filed on Mar. 27, 2013, the entire contents of each ofwhich are hereby incorporated by reference.

BACKGROUND OF THE INVENTIONS

1. Field of the Inventions

The present inventions relate to medical devices for treatment ofpulmonary hypertension in the pulmonary artery by de-sympatheticmethods, for example, with multi-pole synchronous pulmonary arteryradiofrequency ablation catheters, as well as methods for diagnosis andmethod of treating pulmonary hypertension.

2. Description of the Related Art

Pulmonary hypertension (PH) is understood to be an intractable diseasein the cardiovascular, respiratory, connective tissue, immune andrheumatic systems. Currently available clinical treatments of pulmonaryhypertension are limited and therapy efficacy thereof is poor. Incidenceof primary pulmonary hypertension is low, but those secondary topulmonary interstitial fibrosis, connective tissue disease, portalhypertension, chronic pulmonary artery embolism and left heart systemdisorder are common, with five-year mortality rate up to 30%. Therefore,prevention and treatment for pulmonary hypertension is of greatsignificance.

In recent years, new targeted drugs have emerged based on the researchinto the pathogenesis of pulmonary hypertension. However, some of thosedrugs have serious limitations including many side effects,inappropriate dosage form, expensive cost and unreliable efficacy, andthus many have not been widely applied in clinical treatment.

SUMMARY OF THE INVENTIONS

An aspect of at least one of the inventions disclosed herein includesthe realization, supported by experimental data which demonstrates, thatpulmonary hypertension is associated with hyper sympathetic activity inpulmonary artery and hyperactive baroreceptor. Blocking the sympatheticnerves in the pulmonary artery or permanently damaging the baroreceptorstructure and function thereof can decrease the pulmonary arterypressure, which can provide more successful treatments of pulmonaryhypertension.

Some embodiments disclosed herein provide a multi-pole synchronouspulmonary artery radiofrequency ablation catheter for treatment ofpulmonary hypertension in the pulmonary artery by a de-sympatheticmethod. In some embodiments, the catheter only heats the adherent tissuerather than the blood. Additionally, in some embodiments, the cathetercan be configured to provide cold saline perfusion at or near theablation site to protect the vascular intima. Some embodiments can alsoprovide advantages of simple operation, short operation time andcontrollable, precise ablation.

In some embodiments, a multi-pole synchronous pulmonary arteryradiofrequency ablation catheter can comprise a control handle, acatheter body and an annular ring. The control handle can be providedwith an adjustment apparatus. The catheter body can be hollow and caninclude a cavity. One or a plurality of lead wires, one or moretemperature sensing wires and one or more pull wires can be arranged inthe cavity. One end of the catheter body can be flexible. The flexibleend can be connected to an annular ring and the other end of thecatheter body can be connected to the control handle. One end of thepull wire can be connected to the flexible end and the other end of thepull wire can be connected to the adjustment apparatus. Tension in thepull wire can be adjusted through the adjustment apparatus to achieveshape control, such as curvature control, of the flexible end. A shapememory wire can be arranged in the annular ring. One end of the shapememory wire can extend to the end of the annular ring and the other endof the shape memory wire can pass through the root of the annular ringand can be fixed on the flexible end of the catheter body. The annularring can be provided with an electrode group with each electrodeconnected to the one or more lead wires and the one or more temperaturesensing wires. The lead wire(s) and the temperature sensing wire(s)extend through the catheter body and are electrically connected to thecontrol handle.

An infusion tube can be arranged in the cavity of the catheter body anda through hole can be arranged on one or more of the electrodes. Theinfusion tube can be connected to the electrodes through the annularring. The transfused fluid flows out from the through hole and thus canbe used for cooling purposes during ablation as part of the percutaneouspulmonary denervation (PADN) procedure.

The electrodes on the annular ring can be made of material selected froma group consisting of platinum-iridium alloy, gold, stainless steel andnickel alloy, with the number in the range of 3-30 electrodes, adiameter in the range of 1.3-2.0 mm, a length in the range of 1.2-4 mmand an edge space between adjacent electrodes in the range of 0.5-10 mm.

The flexible end of the catheter body can be provided with acounterbore, an inner diameter of the counterbore can be sized to fit anouter diameter of the root of the annular ring, and thus the root of theannular ring can be inserted and fixed into the counterbore.

The flexible end of the catheter body is provided with a groove in whicha connector is arranged, one end of the connector is connected to thepull wire and the other end of the connector is connected to the shapememory wire.

The material of the shape memory wire in the annular ring can be a shapememory alloy selected from a group consisted of nickel-titanium alloy,stainless steel or titanium, with a diameter of 0.25-0.5 mm. Thediameter of the annular ring can be 12-40 mm. For example, the annularring can be configured so as to be biased toward a circumferentialshape, having a desired diameter (e.g., in the range of 12-40 mm), forexample, with the use of a memory shape material. Preferably, 10electrodes are arranged on the annular ring. The width of naked sectionof the electrode is 0.75 mm, and the space therebetween is 5 mm.

The flexible end can be made of medical polymer materials with a lengthin the range of 30-80 mm. The connection can be achieved by a UV-curingadhesive. The joint between the flexible end and the annular ring can besealed.

The pull wire is made of stainless steel or nickel-titanium alloy. Theoutside of pull wire is provided with a spring coil, and the outside ofthe spring coil is provided with a spring sleeve made of polyimidematerial.

In some embodiments, the catheter can be packaged into a kit including aplurality of different annular rings that are biased to differentdiameters. In some embodiments, where the annular rings, flexiblebodies, and handles are permanently connected together, a kit caninclude a plurality of different catheters, each having handles andflexible bodies, but differently sized annular rings.

In some embodiments and/or methods of use, the catheter can heat, withradiofrequency energy, the tissue in direct contact with the electrodeand avoid heating blood. Additionally, the catheter can provideadvantages of simple operation, short operation time and controllableprecise ablation. The catheter body can preferably be made of a polymermaterial, which is a poor heat conductor, so that it can avoidtransmitting the heat when heating the electrodes to the flowing bloodcontacting the catheter body, thereby effectively avoid heating theblood.

Furthermore, the shape or curvature of the flexible end can be adjustedby operating the adjustment apparatus, which allows the operator tocontrol the handle with one hand, so as to easily adjust the curvatureof the flexible end for purposes of placement of the annular ring andthe electrodes. As such, after achieving the desired placement, theelectrodes on the annular ring can be pressed against the pulmonaryartery and achieve ablation of pulmonary artery intima. Duringapplication of the radiofrequency current, the electrodes can producehigh local temperature and cause severe damage on the vascular intima.

Thus, in some embodiments, the catheter can be configured to providecold saline perfusion to cool down the local temperature. When theelectrodes receive current, the saline is automatically and uniformlydiffused through the through holes, which can provide beneficialcooling, for example, decreasing the local temperature to be below 60°C., thereby protecting the vascular intima.

In some embodiments, a multi-pole synchronous pulmonary arteryradiofrequency ablation catheter may comprise a control handle, acatheter body and an annular ring. The control handle may include anadjustment apparatus. The catheter body may be hollow and comprise acavity arranged in the catheter body. A lead wire, a temperature sensingwire and a pull wire may be arranged in the cavity. One end of thecatheter body may be flexible, and the flexible end of the catheter bodymay be connected to the annular ring. The other end of the catheter bodymay be connected to the control handle. One end of the pull wire may beconnected to the flexible end. The other end of the pull wire may beconnected to the adjustment apparatus on the control handle. Theadjustment apparatus may adjust the tension of the pull wire to change acurvature of the flexible end. A shape memory wire may be arranged inthe annular ring. One end of the shape memory wire may extend to an endof the annular ring and the other end of the shape memory wire may passthrough a root of the annular ring and be fixed on the flexible end ofthe catheter body. The annular ring may be provided with an electrodegroup. The electrode group may comprise a first electrode of a firstlength, a second electrode of a second length different than the firstlength, and a third electrode. Each electrode of the electrode group maybe connected to the lead wire and temperature sensing wire. The leadwire and the temperature sensing wire may go through the catheter bodyand be electrically connected to the control handle.

The annular ring may extend from the root of the annular ring to the endof the annular ring and comprise a curve of less than 360 degrees. Theannular ring may extend from the root of the annular ring to the end ofthe annular ring and comprise a curve of more than 270 degrees. Theannular ring may comprise a first diameter and a second diameterdifferent than the first diameter. The first diameter may be at least 25mm and the second diameter may be at least 20 mm.

The electrodes of the electrode group may be substantially coplanar. Thefirst length of the first electrode may be least 4 mm. The second lengthof the second electrode may be least 3 mm. The third electrode maycomprise a third length different than the first length and differentthan the second length. The third length may be at least 2 mm.

In some embodiments, a catheter may comprise a catheter body and anannular ring. One end of the catheter body may be flexible and connectedto the annular ring. The curve of the annular ring may be less than 360degrees and greater than 270 degrees.

The annular ring may be provided with an electrode group comprising afirst electrode of a first length, a second electrode of a second lengthdifferent than the first length, and a third electrode of a third lengthdifferent than the first length and different than the second length.The electrodes of the electrode group may be substantially coplanar andarranged along a curve of the annular ring that extends from a root ofthe annular ring to an end of the annular ring. The first length may beleast 4 mm. The second length may be least 3 mm and may be less than thefirst length. The third length may be least 2 mm and may be less thanthe second length. The first length may be 4 mm. The electrode group maycomprise less than four electrodes.

The first electrode may be separated from the second electrode and thethird electrode by an equal distance. The equal distance may be 1 mm.The first electrode may be farther in distance from a root of theannular ring than the second electrode and the third electrode.

In some embodiments, a controller may comprise a housing, an electronicdisplay, a battery, an electronic data store, and a computing device.The housing may comprise a catheter connection port disposed along asurface of the housing. The connection port may be configured tointerface with a catheter. The catheter may comprise a first electrodeof a first length, and a second electrode of a second length differentthan the first length. The housing may comprise an electronic displaydisposed along the surface of the housing. The housing may envelop abattery, an electronic data store and a computing device. The electronicdisplay may be configured to present a user interface. The battery maybe configured to store power at a level sufficient for ablation usingthe first electrode, or the second electrode. The electronic data storemay comprise stored patient profiles characterizing a plurality ofpatients. The computing device may comprise one or more processors. Thecomputing device may be in communication with the electronic data store,the electronic display and the battery. The computing device may beconfigured to at least: receive a selection of a first patient profileof the stored patient profiles from the user interface, displayinformation characterizing the first patient profile on the userinterface, receive a selection of the first electrode from the userinterface, direct power from the battery at the level sufficient forablation using the first electrode to the first electrode, receive aselection of the second electrode from the user interface, and directpower from the battery at the level sufficient for ablation using thesecond electrode to the second electrode.

The computing device may be configured to direct power from the batteryto the first electrode and direct power from the battery to the secondelectrode at a same time. The computing device may be configured todirect power from the battery to the first electrode and direct powerfrom the battery to the second electrode at different times. Thecomputing device may be configured to interrupt power directed from thebattery to the first electrode and direct power from the battery to thesecond electrode after the power directed from the battery to the firstelectrode is interrupted. The computing device may be configured todirect power from the battery to the first electrode after the batteryhas finished charging. The computing device may be configured to displayon the user interface first electrode ablation information captured bythe first sensor while the first electrode receives power from thebattery. The computing device may be configured to store the firstelectrode ablation information with the first patient profile. Thecomputing device may be configured to display on the user interfacefirst electrode ablation information captured by the first sensor whilethe first electrode receives power from the battery and second electrodeablation information captured by the second sensor while the secondelectrode receives power from the battery. The second electrode ablationinformation may be displayed on the user interface after the firstelectrode stops receiving power from the battery.

The housing may comprise a power connection port configured to receivepower at a level sufficient to charge the battery.

The catheter may comprise a first sensor connected with the firstelectrode. The catheter may comprise a first sensor connected with thefirst electrode and a second sensor connected with the second electrode.

In some embodiments, a computer-implemented method, under control of onemore computing devices executing specific computer executableinstructions, may comprise receiving a selection of a first patientprofile of a plurality of stored patient profiles from a user interfacepresented on an electronic display disposed across a surface of ahousing. The method may comprise displaying information characterizingthe first patient profile on the user interface. The method may comprisereceiving a selection of the first electrode from the user interface.The method may comprise directing power from a battery at the levelsufficient for ablation using the first electrode to the firstelectrode, the battery configured to store power at a level sufficientfor ablation using the first electrode. The method may comprisereceiving a selection of the second electrode from the user interface.The method may comprise directing power from the battery at the levelsufficient for ablation using the second electrode to the secondelectrode. The battery may be configured to store power at a levelsufficient for ablation using the second electrode. The housing maycomprise a catheter connection port disposed along a surface of thehousing. The connection port may be configured to interface with acatheter comprising a first electrode of a first length, and a secondelectrode of a second length different than the first length. Thehousing may envelop the battery, an electronic data store and the one ormore computing devices executing specific computer executableinstructions. The electronic data store may comprise the plurality ofstored patient profiles characterizing a plurality of patients.

The first electrode and the second electrode may be configured toconvert the power from the battery to radiofrequency (RF) energy forablation of sympathetic nerve fibers. The first electrode and the secondelectrode may be configured to convert the power from the battery toultrasonic energy for ablation of sympathetic nerve fibers. The firstelectrode and the second electrode is configured to convert the powerfrom the battery to electroporation energy for ablation of sympatheticnerve fibers. The first electrode and the second electrode may beconfigured to convert the power from the battery to ionizing energy forablation of sympathetic nerve fibers.

In some embodiments, a computer-readable, non-transitory storage mediumstoring computer executable instructions that, when executed by one ormore computer systems, configure the one or more computer systems toperform operations comprising receiving a selection of a first patientprofile of a plurality of stored patient profiles from a user interfacepresented on an electronic display disposed across a surface of ahousing. The operations may comprise displaying informationcharacterizing the first patient profile on the user interface. Theoperations may comprise receiving a selection of the first electrodefrom the user interface. The operations may comprise directing powerfrom a battery at the level sufficient for ablation using the firstelectrode to the first electrode. The battery may be configured to storepower at a level sufficient for ablation using the first electrode. Theoperations may comprise receiving a selection of the second electrodefrom the user interface. The operations may comprise directing powerfrom the battery at the level sufficient for ablation using the secondelectrode to the second electrode. The battery may be configured tostore power at a level sufficient for ablation using the secondelectrode.

The housing may comprise a catheter connection port disposed along asurface of the housing. The connection port may be configured tointerface with a catheter comprising a first electrode of a firstlength, and a second electrode of a second length different than thefirst length. The housing may envelop the battery, an electronic datastore and the one or more computer systems. The electronic data storemay comprise the plurality of stored patient profiles characterizing aplurality of patients.

The directing power from the battery to the second electrode may beperformed by switching power directed from the battery from the firstelectrode to the second electrode. The directing power from the batteryto the second electrode may direct an amount of power greater than anamount of power directed from the battery to the first electrode.

In some embodiments, a multi-pole synchronous pulmonary arteryradiofrequency ablation catheter comprises a control handle, a catheterbody and an annular ring. The control handle may comprise an adjustmentapparatus. The catheter body may be hollow and comprising a cavityarranged in the catheter body. One end of the catheter body may beflexible. The flexible end may be connected to the annular ring. Theother end of the catheter body may be connected to the control handle.One end of the pull wire may be connected to the flexible end, and theother end of the pull wire may be connected to the adjustment apparatuson the control handle. The adjustment apparatus may adjust the tensionof the pull wire to change a curvature of the flexible end. A shapememory wire may be arranged in the annular ring. One end of the shapememory wire may extend to an end of the annular ring and the other endof the shape memory wire may pass through a root of the annular ring andbe fixed on the flexible end of the catheter body. The annular ring maybe shaped with an oval comprising a major axis and a minor axis. Themajor axis may comprise a first diameter along the major axis longerthan a second diameter along the minor axis. The annular ring, extendingfrom the root of the annular ring to the end of the annular ring, maycomprise a curve of less than 360 degrees. The annular ring may anelectrode that straddles the apex of the major axis.

In some embodiments, a catheter comprises a catheter body and an annularring. One end of the catheter body may be flexible and connected to theannular ring. The annular ring may be oval shaped.

The annular ring may comprise a major axis and a minor axis, the majoraxis comprising a first diameter along the major axis longer than asecond diameter along the minor axis. The first diameter may be 5 mmlonger than the second diameter. The major axis may be along a firstaxis of symmetry and the minor axis may be along a second axis ofsymmetry. The annular ring may comprise an electrode that straddles theapex of the major axis. The annular ring may be orthogonal to the end ofthe catheter body that is flexible. The annular ring may be planar. Theannular ring may comprise a curve of less than 360 degrees. The annularring may comprise a curve of less than 360 degrees and greater than 270degrees.

The annular ring may comprise an electrode group comprising a firstelectrode of a first length, a second electrode of a second lengthdifferent than the first length, and a third electrode of a third lengthdifferent than the first length and different than the second length.The electrodes of the electrode group may be substantially coplanar. Thefirst length may be least 4 mm. The second length may be least 3 mm andmay be less than the first length. The third length may be least 2 mmand may be less than the second length. The first length may be 4 mm.The first electrode may be separated from the second electrode and thethird electrode by an equal distance.

In some embodiments, a method of performing pulmonary denervation maycomprise positioning an ablation device in a pulmonary artery trunk of alive animal. The pulmonary artery trunk may include a distal portion ofa main pulmonary artery, a proximal portion of a left pulmonary artery,and a proximal portion of a right pulmonary artery. The method maycomprise deploying an annular ring from the ablation device. The annularring may comprise a major axis and a minor axis. The major axis maycomprise a first diameter along the major axis longer than a seconddiameter along the minor axis. The method may comprise ablating at leastone of the distal portion of the main pulmonary artery, the proximalportion of the left pulmonary artery and the proximal portion of theright pulmonary artery.

In some embodiments, a controller may comprise a housing, an electronicdisplay, an electronic data store, and a computing device. The housingmay comprise a connection port disposed along a surface of the housing.The connection port may be configured to interface with a cathetercomprising a first electrode of a first length, and a second electrodeof a second length different than the first length. The electronicdisplay may be disposed along the surface of the housing. The housingmay envelop the electronic data store and the computing device. Theelectronic display may be configured to present a user interface. Theelectronic data store may comprise stored patient profilescharacterizing a plurality of patients. The computing device maycomprise one or more processors. The computing device may be incommunication with the electronic data store and the electronic display.The computing device may be configured to at least receive a selectionof a first patient profile of the stored patient profiles from the userinterface, display information characterizing the first patient profileon the user interface, and direct power at a first power levelsufficient for ablation using the first electrode to the firstelectrode. The first power level may be based on the first patientprofile. The power may be directed from a power source. The power sourcemay be a battery. The power source may be a wall socket connected to apower grid.

The catheter may comprise a second electrode of a second lengthdifferent than the first length. The computing device may be configuredto direct power at a second power level sufficient for ablation usingthe second electrode to the second electrode. The second power level maybe based on the first patient profile. The second power level may bedifferent than the first power level.

The housing may envelop the battery. The battery may be configured tostore power at the first power level sufficient for ablation using thefirst electrode. The computing device may be in communication with thebattery and configured to direct power from the battery at the firstpower level sufficient for ablation using the first electrode to thefirst electrode. The housing may comprise a power connection portconfigured to receive power at a level sufficient to charge the battery.The computing device may be configured to direct power from the batteryto the first electrode after the battery has finished charging. Thecomputing device may be configured to direct power to the firstelectrode before the battery has finished charging.

The catheter may comprise a first sensor connected with the firstelectrode. The computing device may be further configured to display onthe user interface first electrode ablation information captured by thefirst sensor while the first electrode receives power from the battery.The computing device may be further configured to store the firstelectrode ablation information with the first patient profile. The firstelectrode ablation information may comprise a temperature. The cathetermay comprise an annular ring shaped with an oval comprising a major axisand a minor axis. The major axis may comprise a first diameter along themajor axis longer than a second diameter along the minor axis. The firstelectrode may straddle the apex of the major axis.

In some embodiments, a computer-implemented method may be under controlof one more computing devices executing specific computer executableinstructions. The method may comprise receiving a selection of a firstpatient profile, displaying information characterizing the first patientprofile on a user interface, receiving a selection of the first patientprofile from the user interface, determining, from the first patientprofile, a first power level sufficient for ablation using a firstelectrode, and directing power at the first power level to the firstelectrode.

The first patient profile may be part of a plurality of stored patientprofiles from the user interface presented on an electronic displaydisposed across a surface of a housing. The housing may comprise acatheter connection port disposed along a surface of the housing. Theconnection port may be configured to interface with a cathetercomprising the first electrode. The housing may envelop an electronicdata store and the one or more computing devices executing specificcomputer executable instructions. The electronic data store may comprisethe plurality of stored patient profiles characterizing a plurality ofpatients.

The first electrode may be configured to convert the power toradiofrequency (RF) energy for ablation of sympathetic nerve fibers. Thefirst electrode may be configured to convert the power to ultrasonicenergy for ablation of sympathetic nerve fibers. The first electrode maybe configured to convert the power to electroporation energy forablation of sympathetic nerve fibers. The first electrode may beconfigured to convert the power to ionizing energy for ablation ofsympathetic nerve fibers.

In some embodiments, a computer-readable, non-transitory storage mediumstoring computer executable instructions that, when executed by one ormore computer systems, configure the one or more computer systems toperform operations comprising receiving a selection of a first patientprofile of a plurality of stored patient profiles from a user interfacepresented on an electronic display disposed across a surface of ahousing, displaying information characterizing the first patient profileon the user interface, receiving a selection of the first patientprofile from the user interface, determining, from the first patientprofile, a first power level sufficient for ablation using the firstelectrode, determining, from the first patient profile, a second powerlevel sufficient for ablation using the second electrode, directingpower at the first power level to the first electrode, and directingpower at the second power level to the second electrode.

The housing may comprise a catheter connection port disposed along asurface of the housing. The connection port may be configured tointerface with a catheter comprising a first electrode of a firstlength, and a second electrode of a second length different than thefirst length. The housing may envelop an electronic data store and theone or more computer systems. The electronic data store may comprise theplurality of stored patient profiles characterizing a plurality ofpatients. The directing power to the second electrode may direct anamount of power greater than an amount of power directed to the firstelectrode.

In some embodiments, a controller may comprise a housing, a userinterface, an electronic data store, and a computing device includingone or more processors, the computing device in communication with theelectronic data store, and the user interface. The housing may comprisea connection port disposed along the surface of the housing, a userinterface disposed along the surface of the housing. The housing mayenvelop the electronic data store and the computing device. Theconnection port may be configured to interface with a cathetercomprising a first electrode of a first length, and a second electrodeof a second length different than the first length. The computing devicemay be configured to at least receive a selection of the first electrodefrom the user interface, direct power at a first power level sufficientfor ablation using the first electrode to the first electrode, receive aselection of the second electrode from the user interface, and directpower at a second power level sufficient for ablation using the secondelectrode to the second electrode.

The computing device may be configured to direct power to the firstelectrode and direct power to the second electrode at a same time. Thecomputing device may be configured to direct power to the firstelectrode and direct power to the second electrode at different times.The computing device may be is configured to interrupt power directed tothe first electrode and direct power to the second electrode after thepower directed from the battery to the first electrode is interrupted.

The catheter may comprise an annular ring shaped with an oval comprisinga major axis and a minor axis. The major axis may comprise a firstdiameter along the major axis longer than a second diameter along theminor axis. The first electrode may straddle the apex of the major axis.

The controller may comprise a battery configured to store power at thefirst power level sufficient for ablation using the first electrode orthe second power level sufficient for ablation using the secondelectrode. The housing may envelop the battery. The computing device maybe in communication with the battery and configured to direct power fromthe battery at the first power level sufficient for ablation using thefirst electrode, and direct power from the battery at the second powerlevel sufficient for ablation using the second electrode. The housingmay comprise a power connection port configured to receive power at alevel sufficient to charge the battery. The computing device may beconfigured to direct power from the battery to the first electrode afterthe battery has finished charging. The computing device may beconfigured to direct power from the battery to the second electrodeafter the battery has finished charging.

The catheter may comprise a first sensor connected with the firstelectrode. The computing device may be further configured to display onthe user interface first electrode ablation information captured by thefirst sensor while the computing device directs power to the firstelectrode. The catheter may comprise a first sensor connected with thefirst electrode and a second sensor connected with the second electrode.The computing device may be configured to display on the user interfacefirst electrode ablation information captured by the first sensor whilethe computing device directs power to the first electrode and secondelectrode ablation information captured by the second sensor while thecomputing device directs power to the second electrode. The secondelectrode ablation information may be displayed on the user interfaceafter the computing device stops directing power to the first electrode.

In some embodiments, a computer-implemented method may, under control ofone more computing devices executing specific computer-executableinstructions, comprise receiving a selection of a first electrode on auser interface disposed across a surface of a housing, directing powerat a first power level sufficient for ablation using the first electrodeto the first electrode, receiving a selection of the second electrodefrom the user interface, and switching from directing power to the firstelectrode to directing power at a second power level sufficient forablation using the second electrode to the second electrode. The housingmay comprise a connection port disposed along a surface of the housing,the connection port configured to interface with a catheter comprisingthe first electrode (which may be of a first length), and the secondelectrode (which may be of a second length different than the firstlength). The housing may envelop an electronic data store and the one ormore computing devices executing specific computer-executableinstructions.

The switching may be performed using a mechanical switch that comprisesat least one moving part. The user interface may be a rotatable knob.The switching may be performed using a switching system comprising amechanical switch that comprises at least one moving part, and a solidstate switch that comprises no moving parts.

In some embodiments, a computer-readable, non-transitory storage mediumstoring computer executable instructions that, when executed by one ormore computer systems, may configure the one or more computer systems toperform operations. The operations may comprise receiving a selection ofa first electrode from a user interface presented on an electronicdisplay disposed across a surface of a housing, directing power at afirst power level sufficient for ablation using the first electrode tothe first electrode, receiving a selection of the second electrode fromthe user interface, and switching from directing power to the firstelectrode to directing power at a second power level sufficient forablation using the second electrode to the second electrode. The housingmay comprise a connection port disposed along the surface of thehousing. The connection port may be configured to interface with acatheter comprising the first electrode (of a first length), and thesecond electrode (of a second length different than the first length).The housing may envelop an electronic data store and the one or morecomputer systems. The switching may be performed by controlling a solidstate switch that comprises no moving parts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of an embodiment of a catheterin accordance with an embodiment;

FIG. 2 is a partially enlarged view of Part B identified in FIG. 1;

FIG. 3 is schematic sectional view taken along line A-A′ of FIG. 1;

FIG. 4 is a schematic structural view of an optional outer surface of anelectrode that can be used with the catheter of FIG. 1;

FIG. 5 is a front elevational and partial sectional view of a humanheart;

FIG. 6 is a schematic sectional diagram of a pulmonary artery trunkincluding a distal portion of a main pulmonary artery and the proximalportions of the left and right pulmonary arteries;

FIGS. 7A and 7B are photographs of the inner surfaces of two caninepulmonary arteries that have been dissected and laid flat;

FIG. 8 is a schematic diagram of segmentations of dissected pulmonaryarteries including the distal portion of the main pulmonary artery andthe proximal portions of the left and right pulmonary arteries;

FIG. 9 is a diagram of three of the segmentations identified in FIG. 8;

FIGS. 10A-10D are enlargements of microscopy slides corresponding to theportions identified as S1-S4 of level A1 of the right pulmonary arteryof FIG. 9;

FIG. 11 is a photograph of microscopy of the portion identified as S6 oflevel A9 of the main pulmonary artery of FIG. 9;

FIG. 12 is a posterior and perspective view of a model of the leftpulmonary artery of FIGS. 7A and 7B;

FIG. 13 is an anterior view of the left pulmonary artery of FIG. 12;

FIG. 14A is a diagram identifying the location corresponding tomicroscopy of six different locations on level A9 of the main pulmonaryartery of FIG. 8;

FIG. 14B is a table showing reductions in pulmonary artery pressure(PAP) resulting from the use of different ablation operating parameters;

FIG. 15A is a perspective view of a catheter that can be used to performpulmonary denervation;

FIG. 15B is an enlarged end view of a distal end of the catheter of FIG.15A with indicia indicating positions of ten (10) RF electrodes;

FIG. 15C is a perspective view of a controller that can be used forcontrolling the catheter of FIG. 15A during an ablation procedure;

FIG. 15D is a top plan view of the controller of FIG. 15C;

FIG. 15E is a perspective view of the controller connected to thecatheter of FIG. 15A;

FIG. 16A is a fluoroscope image of a sheath device inserted into themain pulmonary artery for guiding the catheter of FIG. 15A into the mainpulmonary artery;

FIGS. 16B-16D are additional fluoroscope images of the catheter of FIG.15A having been inserted and expanded within the left pulmonary arteryof a human patient;

FIG. 16D illustrates a position used for ablation and arterialdenervation of the left pulmonary artery of the patient;

FIG. 16E illustrates the catheter of FIG. 15A being positioned withinthe main pulmonary artery of the patient in a position used forablation;

FIGS. 16F and 16G illustrate the catheter of FIG. 15A being positionedin the proximal right pulmonary artery and being pushed (FIG. 16F) andpulled (FIG. 16G) to determine if the catheter is properly seated forpurposes of ablation;

FIG. 16H is a fluoroscope image of the catheter of FIG. 15A in aposition for performing ablation in a proximal portion of the rightpulmonary artery;

FIG. 17A is a schematic diagram of the trunk of a pulmonary artery andidentifies locations for ablation in a distal portion of a mainpulmonary artery;

FIG. 17B is a schematic diagram of a pulmonary artery trunk andidentifies locations for ablation in proximal portions of the left andright pulmonary arteries;

FIG. 18A is a schematic diagram of a pulmonary artery trunk identifyinga position for ablation in a portion of the left pulmonary arteryproximal to a pulmonary artery duct;

FIG. 18B is a schematic diagram of points of ablation in the anteriorwall of the ablation position identified in FIG. 18A;

FIG. 19A is a schematic diagram of a pulmonary artery trunk identifyinga position for ablation in a proximal portion of the right pulmonaryartery for treatment of unilateral chronic thrombotic embolism;

FIG. 19B is an enlarged schematic diagram of the portion identified inFIG. 20A and indicates positions for ablation in the anterior wall ofthe proximal portion of the right pulmonary artery;

FIG. 20 is a schematic diagram of a pulmonary artery trunk including adistal portion of a main pulmonary artery and the proximal portions ofthe left and right pulmonary arteries;

FIG. 21 is a schematic diagram of optional points of ablation alongLevel C identified in FIG. 20, proximate to a transition between a leftlateral wall of the main pulmonary artery and a lower wall of aproximate portion of the left pulmonary artery;

FIG. 22A is an enlarged perspective view of a further embodiment of thecatheter of FIGS. 1 and 15A with indicia indicating positions of five(5) RF electrodes;

FIG. 22B is an enlarged perspective view of a further embodiment of thecatheter of FIGS. 22A with three (3) electrodes;

FIGS. 23A-23C are angiographs illustrating parts of the PADN procedure;

FIG. 24A is a chart illustrating the 6-minute walk distance (6MWD) atthe 6-month follow-up minus the baseline 6MWD in the Medicationtreatment and the PADN procedure;

FIG. 24B is a chart illustrating how the 6MWD after the PADN procedureis correlated with a Medication treatment;

FIG. 24C is a chart illustrating how improvements in hemodynamic andcardiac functions were sustained through a one-year follow-up after thePADN procedure.

FIGS. 25A-25H are various perspective views and user interfacescreenshots of a digital ablation controller.

FIG. 26 is a schematic diagram illustrating a mechanical switchingsystem that may be implemented in the controller of FIGS. 25A-25H or thecontroller of FIGS. 15C-15D.

FIG. 27 is a schematic diagram illustrating a solid state switchingsystem that may be implemented in the controller of FIGS. 25A-25H or thecontroller of FIGS. 15C-15D.

FIG. 28 is a diagram illustrating a generic switching system that may beimplemented in the controller of FIGS. 25A-25H or the controller ofFIGS. 15C-15D.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following examples further illustrate embodiments of the presentinventions, but should not be considered as to limit the presentinventions. Without departing from the spirit and essence of the presentinventions, modification or replacement of the method, steps orconditions of the embodiments disclosed below still falls in the scopeof the present inventions.

If not otherwise specified, the technical means used in the embodimentsare conventional means well known by a person skilled in the art.

Example 1

Through the example below and with reference to FIGS. 1-3, some of thetechnical solutions that can be achieved by various embodiments arefurther described below.

In some embodiments, a multi-pole synchronous pulmonary arteryradiofrequency ablation catheter for de-sympathetic ablation in thepulmonary artery can include a catheter body 1 that has a distal end anda proximal end. The distal end can be provided with a flexible end 3 andthe proximal end can be provided with a control handle 2. A pull wirecan extend in the catheter body.

Preferably, the catheter body can be made of a polymer material, whichis a poor heat conductor, so that it can avoid transmitting or reducingthe amount of heat transferred from the electrodes to the blood flowcontacting the catheter body, and thereby can better prevent theelectrode from heating the blood flow.

The flexible end 3 can include a proximal end and a distal end. Anannular ring 4 can be arranged on the distal end. The flexible end 3 canbe soft relative to the rest of the catheter body. The annular ring 4can be provided with a plurality of electrodes 5, wherein each electrode5 can be configured to sense or extract neural electrical signals, sensetemperature and conduct ablation. Each of the electrodes can beconnected to lead wires and temperature sensing wires, which extendthrough the catheter body to the control handle, thus is electricallyconnected to the control handle. One or more temperature sensing wirescan be embedded under each electrode for precise monitoring of thetemperature during ablation. Additionally, in some embodiments, thetemperature sensing wires can be connected to a thermocouple connectedto an inner facing side of the electrodes 5, or can include integratedthermocouples. Other configurations can also be used.

In accordance with several embodiments, ablation may be performed by theelectrodes 5 using radiofrequency (RF) energy to ablate sympatheticnerve fibers to cause neuromodulation or disruption of sympatheticcommunication. In some embodiments, the electrodes 5 may use ultrasonicenergy to ablate sympathetic nerve fibers. In some embodiments, theelectrodes 5 use ultrasound (e.g., high-intensity focused ultrasound orlow-intensity focused ultrasound) energy to selectively ablatesympathetic nerve fibers. In other embodiments, the electrodes 5 useelectroporation to modulate sympathetic nerve fibers.

However, the electrodes 5, as used herein, shall not be limited tocausing ablation, but also include devices that facilitate themodulation of nerves (e.g., partial or reversible ablation, blockingwithout ablation, or stimulation). In some embodiments, the catheter mayuse agents offloaded at the location of the electrodes 5 to nerve fibersto modulate the nerve fibers (e.g., via chemoablation). Chemical agentsused with chemoablation (or some other form of chemically-mediatedneuromodulation) may, for example, include phenol, alcohol, or any otherchemical agents that cause chemoablation of nerve fibers. In someembodiments, cryotherapy is used. For example, the catheter may useagents offloaded at the location of the electrodes 5 for cryoablation toselectively modulate (e.g., ablate) sympathetic nerve fibers. In otherembodiments, the catheter may use brachytherapy to modulate the nervefibers. The catheter may further utilize any combination of RF energy,microwave energy, ultrasonic energy, focused ultrasound (e.g., HIFU,LIFU) energy, ionizing energy (such as X-ray, proton beam, gamma rays,electron beams, and alpha rays), electroporation, drug delivery,chemoablation, cryoablation, brachytherapy, or any other modality tocause disruption or neuromodulation (e.g., ablation, denervation,stimulation) of autonomic (e.g., sympathetic or parasympathetic) nervefibers.

In accordance with some embodiments, the neuromodulation system is usedto modulate or disrupt sympathetic nerve fibers at one or more locationsor target sites. For example, the catheter may perform ablation in acircumferential or radial pattern (such as by using the annular ring 4),and/or the catheter may perform ablation at a plurality of pointslinearly spaced apart along a vessel length. In other embodiments, thecatheter performs ablation at one or more locations in any other patterncapable of causing disruption in the communication pathway ofsympathetic nerve fibers (e.g., spiral patterns, zig-zag patterns,multiple linear patterns, etc.). The pattern can be continuous ornon-continuous (e.g., intermittent). The ablation may be targeted atcertain portions of the circumference of the vessels (e.g., half orportions less than half of the circumference).

A shape memory wire can be arranged in the annular ring 4, and a distalend of the shape memory wire can extend to the distal end of the annularring 4. The proximal end of the shape memory wire can be fixed to thedistal end of the flexible end 3. The shape memory wire in the annularring 4 can preferably be made of various shape memory alloys such asnickel-titanium alloy, stainless steel or titanium, with a diameter inthe range of 0.25-0.5 mm.

The diameter of the annular ring 4 is in the range of 12-40 mm. Forexample, the shape memory wire can be configured to bias the annularring 4 to a desired diameter, such as in the range of 12-40 mm.Additionally, in some embodiments, the pull wire can be used to changeor adjust the diameter of the annular ring 4 through a range ofdiameters including 12-40 mm or other ranges.

The length of the flexible end 3 can be in the range of 30-80 mm and canbe made of medical polymer materials such as fluorine, polyesters,polyurethane, polyamide and polyimide. A counterbore can be arranged onthe distal end of the flexible end 3, the proximal end of the annularring can be fixed in the counterbore, wherein the proximal end of theannular ring is a ground thin end.

A pull wire can be embedded in the catheter body, and one end of thepull wire can be fixed to the control handle. The curvature of theflexible end 3 can be controlled by operating the control handle. Forexample, one end of the pull wire can be fixed to a control button onthe handle and the curvature of the flexible end 3 can be controlled byoperating the button. This allows the operator to control the handlewith one hand and adjust the curvature of the flexible end 3 easily, sothat the electrodes 5 on the annular ring 4 can be pressed into contractwith the pulmonary artery and achieve acceptable ablation of pulmonaryartery intima.

Furthermore, a counterbore can be made on the distal end of the flexibleend 3, and its depth can be set according to actual needs, preferablywith a depth in the range of 2-8 mm. The proximal end of the annularring 4 can be a ground thin end, and an outer diameter of the groundthin end fits an inner diameter of the counterbore. The ground-thin endcan be inserted into the flexible end 3 and can be fixed to the distalend of the flexible end 3 by bonding, welding or other suitable means,preferably by UV-curing adhesive. Excess glue may be used to seal thedistal end of the flexible end 3 and the proximal end of the annularring 4.

FIG. 1 shows a schematic structural diagram of the multi-polesynchronous pulmonary artery radiofrequency ablation catheter. Theannular ring 4 can be arranged at the distal end of the flexible end 3.The annular ring 4 can be an annular structure, and the radius of theannular ring 4 can be effected with shape memory wire.

The annular ring 4 can be provided with a plurality of electrodes 5.Each electrode 5 can be configured to extract or detect neuralelectrical signals, sense the temperature and conduct ablation. Thenumber of electrodes 5 can vary from the range of 3 to 30, preferably 5to 20. The electrodes 5 are made of platinum-iridium alloy, gold,stainless steel or nickel alloy. The electrode diameter can be generally1.3-2.0 mm, and the length of the electrode 5 can be generally in therange of 1.2-4 mm, more suitably 2-3.5 mm. Edge space between theadjacent electrodes suitably can be in the range of 0.5-10 mm, moresuitably 1-5 mm.

The pull wire 8 can preferably be made of stainless steel ornickel-titanium. As shown in FIG. 2 and FIG. 3, the distal end of thepull wire 8 extends through a hollow cavity 9 to the proximal end of theannular ring 4, and can be fixed to the distal end of the flexible end3. The method used for fixing the pull wire 8 to the distal end of theflexible end 3 can be any known method in the prior art.

Optionally, a groove can be arranged on the distal end of the flexibleend 3, and a connector 11 can be arranged in the groove. One end of theconnector 11 can be connected to the pull wire 8 and the other end ofthe connector 11 can be connected to the shape memory wire 12. Theconnector 3 can be fixed to the distal end of the flexible end 3 byinjecting glue such as UV-curing adhesive into the groove.

A segment of pull wire 8 extends in the flexible end 3 and a segment ofpull wire 8 extends in the catheter body 1. The pull wire can preferablybe jacketed with a coil spring 13, and the coil spring 13 can bejacketed with a spring sleeve 14. The spring sleeve 14 may be made ofany suitable material, preferably a polyimide material.

The proximal end of the pull wire 8 can be fixed on or in the controlhandle 2, which can be provided with an adjustment apparatus, and theadjustment apparatus can be configured to adjust the curvature or thediameter of the annular ring 4.

Lead wire 6, as shown in FIG. 2 and FIG. 3, extends through the leadwire cavity 10 to the lead wire cavity of the annular ring 4. The distalend of the lead wire 6 can be connected to electrode 5. The distal endof the lead wire 6 can be fixed to electrode 5 by welding. In someembodiments, the catheter includes one lead wire 6 for each of theelectrodes 5.

The distal end of the temperature sensing wire 7 can be embedded underthe electrode 5 and the distal end of the temperature sensing wire 7 canbe fixed on electrode 5 by bonding, welding or other suitable means. Thetemperature sensing wire 7 can extend into the catheter body 1 in thelead wire cavity 10 of the flexible end 3 and then extend out from thecontrol handle 2 and can be connected to a temperature control device.In some embodiments, the catheter includes one temperature sensing wire7 for each of the electrodes 5.

When using the catheter, the pull wire 8 can be operated through thecontrol handle 2 in order to deflect the flexible end 3, therebyproviding enhanced control for the user when positioning the annularring 4 in a desired location, such as an orifice of the pulmonaryartery. At this time, the electrodes 5 can be energized for performingablation on pulmonary artery intima.

The multi-electrode design according to some embodiments can improve theefficacy and safety of ablation, and achieve signal analysis andpreferably simultaneous ablation by a plurality of electrodes. This canalso improve target accuracy, achieve timely judgment of ablation effectand save operation time. For example, with the annular ring 4 in adesired location, the electrodes can be individually activated toperform ablation at selected sites. This can be a benefit because insome methods of treatment described below, ablation can be performed atselected sites, less than the entire circumferential surface of certainanatomy.

Example 2

A multi-pole synchronous pulmonary artery radiofrequency ablationcatheter comprises a control handle 2, a catheter body 1, and an annularring 4. The control handle 2 can be provided with an adjustmentapparatus, the catheter body 1 can be hollow, and a cavity can bearranged in the catheter body 1. One or more lead wires 6, temperaturesensing wires 7, and a pull wire 8 can be arranged in cavity.

One end of catheter body can be flexible, and the flexible end 3 can beconnected to the annular ring 4. The other end of the catheter body canbe connected to the control handle 2. One end of the pull wire 8 can beconnected to the flexible end 3, and the other end of the pull wire 8can be connected to the adjustment apparatus of the control handle, andthe adjustment apparatus adjusts the tension of the pull wire 3 tocontrol the curvature of the flexible end. This allows the operator tocontrol the handle with one hand and adjust the curvature of theflexible end 3 easily. Thereby the electrodes 5 of the annular ring 4can be pressed against to better contact an inner surface of a desiredanatomy, such as a pulmonary artery, so as to enhance ablation ofpulmonary artery intima.

A shape memory wire 12 can be arranged in the annular ring 4. One end ofthe shape memory wire 12 can extend to the end of the annular ring 4,and the other end of the shape memory wire 12 goes through the root ofthe annular ring 4 and can be fixed on the flexible end 3 of thecatheter body.

The annular ring 4 can also be provided with an electrode group. Eachelectrode 5 can be connected to a lead wire 6 and a temperature sensingwire 7 and can be configured to extract or detect the nerve electricalsignals, sense the temperature and conduct ablation. The lead wires 6and temperature sensing wires 7 can extend through the catheter body 1and can be electrically connected to the control handle 2. The controlhandle 2 can be connected to an external temperature control device.

The annular ring electrodes 5 can be made of a material selected from agroup consisting of platinum-iridium alloy, gold, stainless steel andnickel alloy material, with the number in the range of 3-30, a diameterin the range of 1.3- 2.0 mm, a length in the range of 1.2-4 mm and anedge space between adjacent electrodes in the range of 0.5-10 mm.

The flexible end 3 of the catheter body can have a counterbore 32. Anouter diameter of the root of the annular ring 4 can fit an innerdiameter of the counterbore 32. The root of the annular ring 4 can beinserted into the counterbore 32 and fixed.

The flexible end 3 of the catheter body can be provided with a groove. Aconnector 11 can be arranged in the groove. One end of the connector canbe connected to the pull wire 8 and the other end of the connector canbe connected to the shape memory wire 12.

The shape memory wire 12 can be made of shape memory alloy such asnickel-titanium alloy, stainless steel or titanium, with a diameter inthe range of 0.25-0.5 mm. The diameter of the annular ring 4 can be inthe range of 12-40 mm. Preferably, 10 electrodes are arranged on theannular ring, and the width of naked (exposed) side of electrodes can be0.75 mm, and the space there between can be 5 mm.

The flexible end 3 of the catheter body can be made of medical polymermaterials such as fluorine, polyesters, polyurethane, polyamide andpolyimide, with a length in the range of 30 mm to 80 mm.

The connection can be via UV-curing adhesive. The joint between theflexible end of the catheter body and the annular ring can be sealed.The pull wire 8 can be made of stainless steel or nickel-titanium alloy.The pull wire 8 can be jacketed with a coil spring 13, and the coilspring 13 can be jacketed with a spring sleeve 14 made of polyimidematerial.

Example 3

Example 3 is similar to Example 1 and Example 2, and the differences caninclude an infusion tube 22 arranged in the catheter body, a group ofevenly distributed through holes 15 (FIG. 4) arranged on one or more ofthe electrodes 5, with a bore diameter of 1 μm. One end of the infusiontube 22 can be connected to the electrodes 5 through the annular ring 4such that fluid diffuses out from the through holes 15 on each of theelectrodes 5. For example, the annular ring 4 can include or define atleast one lumen 24 extending between a proximal end of the annular ring4 and to the through holes 15 so as to form a closed fluidic connection.In such embodiments, a distal end of the infusion tube 22 can beconnected to the proximal end of the lumen 24 in the annular ring 4. Theother end of the infusion tube 22 can be connected to a transfusionsystem, such as a constant-flux pump or other known pumps.

When electrodes 5 generate current, the liquid automatically diffusesfrom the through holes 15. The transfused liquid can be saline. The coldsaline (4° C.) perfusion can help decrease local temperature. When theelectrode generates current, the saline can automatically diffuse fromthe through holes 15, and thus can allow the local temperature to becontrolled to a desired temperature, such as to below 60° C. and therebyprotect the vascular intima.

FIG. 5 is a schematic diagram of a human heart and surroundingvasculature, which can be an environment in which the catheter of FIGS.1-4 can be used to perform ablation treatments such as, for example, butwithout limitation, denervation of the pulmonary artery. In some methodsof treatment, access to the inner walls of the main pulmonary artery 502as well as the left pulmonary artery 504 and right pulmonary artery 506can be achieved by passing a catheter, using well known techniques, intoa femoral vein, upwardly into the inferior vena cava 508 (lower lefthand corner of FIG. 5). The catheter can then be pushed upwards into theright atrium 510, down into the right ventricle 512, then up through thepulmonary semilunar valve 514 into the trunk of the main pulmonaryartery 502. As used herein, the term main pulmonary artery (MPA) 502includes the proximal end of the main pulmonary artery which is thefurthest upstream end of the main pulmonary artery 502, at the pulmonarysemilunar valve 514, up to the bifurcation of the main pulmonary artery.The distal portion of the MPA 502 includes the portions of the MPA 502near the bifurcation of the MPA 502 into the left and right pulmonaryarteries (LPA 504, RPA 506).

Similarly, the proximal ends of the RPA 506 and LPA 504 are those endsof the LPA 504 and RPA 506 which are adjacent and connected to thedistal end of the MPA 502. The distal direction along the LPA 504 andRPA 506 would be the downstream direction of blood flow through the LPA504 and RPA 506 toward the left and right lungs, respectively.

Thus, using well known techniques, a catheter can be used to provideaccess to the proximal and distal portions of the MPA 502 as well as theproximal and distal portions of the LPA 504 and RPA 506.

FIG. 6 is a schematic diagram of the “trunk” of the pulmonary artery. Asused herein, the “trunk” of the MPA 502 is intended to include at leastthe distal portion of the MPA 502 and the proximal portions of the LPA504 and RPA 506. FIG. 6 also includes a schematic representation of acarina 602 at the branch of the LPA 504 and RPA 506 from the MPA 502.

As described below, an aspect of at least some of the inventionsdisclosed herein includes the realization that the trunk of thepulmonary artery of certain animals, including canine and humans, caninclude concentrated bundles of sympathetic nerves extending from theMPA 502 into the LPA 504 and RPA 506. For example, it has beendiscovered that there are higher concentrations of sympathetic nerves onthe anterior sides of the MPA 502 and in particular, in the vicinity ofthe distal portion of the MPA 502. Additionally, it has been discoveredthat the sympathetic nerves bifurcate from this area of higherconcentration into the anterior side of the proximal portions of the LPA504 and RPA 506. In the area of these proximal portions, it has alsobeen discovered that higher concentrations of the sympathetic nervesextend upwardly and toward the posterior side of the LPA 504 and RPA506.

Thus, in accordance with some of the inventions disclosed herein,ablation is performed in the distal portion of the MPA 502 and theproximal portions of the LPA 504 and RPA 506. In some embodimentsablation is preferentially performed on the anterior side of the innerwalls of these structures. In some embodiments, ablation is performedpreferentially on the anterior side of the proximal portion of the MPA502 and on the anterior side and an upper portion of the proximalportions of the LPA 504 and RPA 506, such as at approximately the upperconjunctive site of the distal portion of the MPA 502 at the LPA 504 andRPA 506. As such, high success rates of sympathetic nerve denervationcan be achieved as well as high success rates of reduction orelimination of the symptoms of pulmonary hypertension.

It is widely accepted that all vascular walls are regulated bysympathetical and parasympathetical nervous systems. Particularly,pulmonary vessels are known to be innervated by sensory nerve fibers.Previous studies have demonstrated that sympathetic noradrenergicinnervation density along the pulmonary artery is highest at itsproximal segments and then decreases toward the periphery, a typicalfinding that is different than arteries in other organs where highestinnervation density is found at the level of the smallest arterioles.However, the conclusions of the above-noted study were based onprocedures in which the identification of innervation in the pulmonaryartery was mainly based on the stimulation of sympathetical nerves orequivalent methods, without direct evidence or other location ofsympathetical nerve fibers. However, it has been discovered that some ofthe conclusions of the above-noted study are incorrect, through the useof techniques for identifying the presence and location of sympatheticalnerves in the pulmonary artery using direct labeling techniques.

In particular, experimental procedures were approved by theInstitutional Animal Care and Use Committees of the Nanjing MedicalUniversity and were performed in accordance with the National Guide forthe Care and Use of Laboratory Animals. Mongolia dogs (n=6, weight7.8±1.2 kg) were obtained from the Nanjing Experimental Center (Nanjing,China). All animals were housed in a single room at 24° C. on a 12h-light/12 h-dark cycle with fresh food and water.

In this study, a dog was anesthetized with sodium pentobarbital (60 mgper kg, intraperitoneal injection). The chest was excised and openedcarefully. The whole pulmonary artery was removed from the chest, withparticular attention to avoid the injury of adventitia. In one dog, thepulmonary artery was longitudinally cut along the blood flow directionfrom the orifice of the main pulmonary artery (the proximal portion ofthe main pulmonary artery) toward the right and left branches. Then, avernier focusing camera was used to take pictures in order to identifywhether there is a visible difference in the surface of the pulmonaryartery between different segments.

With regard to five other dogs, connective tissue was manually dissectedaway from the pulmonary artery using fine microdissection scissors,under the guidance of stereomicroscope. During this procedure, greatcare was taken to avoid stripping off the adventitia and possible damageto the perivascular nerves. Vessels were stored at −70° C. for furtherstaining.

Frozen vessels were processed in paraffin wax and fixed in 4%paraformaldehyde for 30 minutes and then incubated at 0.5% Pontamine SkyBlue (Sigma-Aldrich, St. Louis, Mo.) in phosphate-buffered saline (PBS)for 30 minutes to reduce background fluorescence. This was followed by 1hour at room temperature in a blocking solution of 4% normal goat serum/0.3% Triton X-100 in PBS, then overnight at 4° C. in blocking solutioncontaining an affinity-purified polyclonal antibody against tyrosinehydroxylase (Temecula, Calif.). Vessel segments were then washed in PBSand incubated for 1 hour with secondary antibody (Invitrogen, Carlsbad,Calif), washed again and positioned on a glass slide. Preparationsremained immersed in PBS during image acquisition to maintain hydrationand preserve vessel morphology.

Based on previous studies, the sympathetical nerves were thought to bemainly localized at the proximal segment of the pulmonary artery. Thusthe distal segment (5 mm in length) of the main pulmonary artery andproximal 5 mm segments of the right and left branches were selected forinvestigation in the present study. FIG. 6 schematically illustrates,not to scale, a 5 mm segment of the distal portion of the MPA and 5 mmlong proximal portions of the LPA and RPA.

Multiple transverse slices (2 μm of thickness) of the vessels were cutat 1.6 mm intervals and are identified in the description set forthbelow in accordance with the labels of FIG. 8 (A1, A2, A3, A4, A5, A6,A7, A8, A9, A10, A11, A12). Care was taken to keep the luminalmorphology of slices consistent with the vessel contour, in order toprecisely position the location of nerves. The slices were examined by apathologist.

Images of each slice were recorded (magnification 40× to 200×) usingstereomicroscope (Olympus), and the numbers of total sympatheticalnerves bundles (SPNDs) per level were manually calculated. Then allimages were input to Image Analysis Software (Image-proplus 5.0), tocalculate the minor radius (μm), major radius (μm) and total surfacearea (TSA, μm²×10³) area of axons.

After the pulmonary artery was removed from the chest of the dog, thepulmonary artery was repeatedly cleaned with saline to clean away allblood on the surface of the vessel. Then the whole vessel was cut alongthe direction from the proximal portion of the main pulmonary artery upthrough the trunk and into the right and left branches. The above-notedpictures (FIGS. 7A, 7B) showed that in the anterior wall of the mainpulmonary artery, there was an obvious ridgy cystica 702 close to theorifice of the left pulmonary artery. The site of the ridgy cystica 702felt rigid to the touch, compared to other areas of the pulmonaryartery.

In the vicinity of the bifurcation portion of the pulmonary artery,segments 5 mm in length of the distal main pulmonary artery and theproximal portions of the right and left pulmonary arteries were studied.Four transverse slices (thickness 2 μm, 1.6 mm intervals) from eachsegment were prepared for analysis. Each slice (“level”) was dividedinto 4 subsegments in the right and left pulmonary arteries (S1, S2, S3,S4 in FIG. 9)_and 6 subsegments in the main pulmonary artery along thecounterclockwise direction (S1, S2, S3, S4, S5, S6 in FIG. 9).

Upon inspection of these samples, it was observed that more SPNDs 1002were identified in the posterior wall in both the left and rightpulmonary arteries (FIG. 10A). However the number of SPNDs 1002 was1.6±0.2 in the 51 subsegment of the A5 level in the left pulmonaryartery branch, significantly different from 1.2±0.2 in the S1 subsegmentof level A1 in the right pulmonary artery (p=0.033). In contrast, moreSPNDs 1002 were labeled in the anterior wall (S6) of the main pulmonaryartery (FIG. 11) and decreased gradually from the levels A9 to A12.

The minor and major radii of sympathetical axons in the main pulmonaryartery were 85±2 μm and 175±14 μm, compared to 65±3 μm and 105±12 μm inthe left pulmonary artery or 51±2 μm and 86±8 μm in the right pulmonaryartery, respectively, resulting in significant differences in surfacearea of axons between the main pulmonary artery and the LPA and RPA(FIG. 9).

Based on the results of the above-described observations, it has beendetermined that in canines, sympathetical nerves are distributed inhigher concentrations along the anterior wall of the main pulmonaryartery, then extend into the left and right pulmonary arteries, thenextend upwardly and then toward the posterior walls of the left andright pulmonary arteries, as schematically represented in FIG. 12 andFIG. 13.

Further, inspection of subsegment S6 in level A9 (FIG. 11) of the MPA(magnification 200×) revealed that a bundle or main bundle ofsympathetical nerves originate from approximately the middle of theanterior wall of the distal portion of the main pulmonary artery andthat this main bundle is bifurcated to the left and right pulmonaryarteries.

This discovery provides a basis for more effective denervation of thepulmonary artery. For example, by selectively ablating only portions ofthe main pulmonary artery and the left and right pulmonary arteries, ahigher success rate of denervation can be achieved with less unnecessarytissue damage. Such denervation can provide significant benefits in thetreatment of diseases such as pulmonary hypertension, as describedbelow.

With regard to the disease of pulmonary hypertension, it is well knownthat the lung receives axons from principal sympathetic neurons residingin the middle and inferior cervical and the first five thoracic ganglia(including the stellate ganglion), and the vasculature is the majorsympathetic target in the lung. Sympathetic nerve stimulation increasespulmonary vascular resistance and decreases compliance, which ismediated by noradrenaline via a-adrenoreceptors, primarily of thea1-subtype.

Previous studies have confirmed the multiplicity of transmittersreleased from one nerve ending which might explain why pharmacologicalblockade of the “classical” transmitter alone does not effectivelyabolish the effects elicited by nerve stimulation. The present studyexplained above supports the concept that more successful sympatheticaldenervation along the pulmonary trunk can be enhanced at the proximalsegments of the left and right pulmonary arteries rather than at thedistal basal trunks. Further, the percutaneous pulmonary denervation(PADN) procedure has potential for decreasing pulmonary pressure andresistance induced by unilateral balloon occlusion in the interlobarartery. However, until now, there was a lack of data showing thedistribution of sympathetical nerves in the pulmonary trunk. Thus, theaccurate identification of the position of sympathetical nerves isimportant for performing a successful PADN procedure. In the presentstudy, significantly larger bundles of sympathetical nerves wereidentified in the mid-anterior wall of the distal portion of the mainpulmonary artery, which is bifurcated into the posterior wall of theleft and right pulmonary arteries. These results imply that one or moreablation procedures, for example, by the PADN procedure, especiallyaround the distal portion of the main pulmonary bifurcation and theproximal portions of the LPA and RPA are more likely to provide enhancedresults and more successful denervation, as was suggested in the animalstudy noted above.

It is noted that sympathetic noradrenergic innervation density ishighest at the large extra-pulmonary and hilar blood vessels, botharteries and veins, and then decreases toward the periphery. This is inmarked contrast to many other organs, in which the highest innervationdensity is found at the level of the smallest arterioles. Suchdistribution varies from species to species with regard to the extent towhich the sympathetic noradrenergic axons reach into the lung. In guineapigs, rabbits, sheep, cats, dogs, and humans, small arteries down to 50μm in diameter are innervated, whereas in rats, mice, hedgehogs, andbadgers, noradrenergic innervation stops close to the lung.

An extensive network of noradrenergic and NPY-containing fibers has beennoted around pulmonary arteries of several species, but only a fewstudies used double-labeling techniques to evaluate the extent ofcolocalization. In the guinea pig, principally all noradrenergic fibersinnervating pulmonary arteries and veins contain NPY and, in addition,dynorphin, a neuropeptide of the opioid family. In this aspect,pulmonary vascular innervation differs markedly from that of skinarteries in the same species, wherein three different combinations ofnoradrenaline, NPY, and dynorphin are used by sympathetic axons. Each ofthese populations is restricted to a specific segment of the arterialtree in the skin. Still, noradrenergic and NPY-containing fibers do notmatch 1:1 in the lung either, as there is a minor population of axonsinnervating guinea pig pulmonary arteries and veins that contains NPYplus vasoactive intestinal peptide (VIP) but not noradrenaline. Itremains to be clarified whether this less-frequent fiber populationrepresents the non-noradrenergic neurons projecting to the guinea piglung or originates from other systems.

The present study explained above, which relied on the serial slicing atvarious levels through the pulmonary artery trunk, demonstrates thatlarger bundles of nerves are more localized in the anterior wall of themain pulmonary artery and then bifurcate into the left and rightpulmonary arteries along the posterior walls of the LPA and RPA. Theabove study was performed on canine anatomy.

One of the diseases that can be treated with the present methods anddevices is idiopathic pulmonary arterial hypertension (IPAH). IPAH ischaracterized by elevations of mean pulmonary artery pressure (PAP) andpulmonary vascular resistance (PVR). The pathogenesis of IPAH wasbelieved to be due to imbalance between locally produced vasodilatorsand vasoconstrictors. Recent studies have demonstrated that vascularwall remodeling also contributed to elevated PVR. The role of neuralreflex in the mediation and development of IPAH has not beenspecifically investigated. The present animal study described abovedemonstrates that the PADN procedure can reduce or completely abolishelevations of PAP induced by balloon occlusion at interlobar segments,but not at the basal trunk.

In a further phase of the present study, a human study was conducted.Prior to enrollment, all 21 patients received a diuretic(hydrochlorothiazide at a dose of 12.5 mg to 25 mg, once daily, and/orspironolactone at a dose of 20 mg to 40 mg, once daily) and beraprost(120 mg, 4 times daily) (Table 1), with either sildenafil (20 mg, 3times a day) or bosentan (120 mg, twice daily) or digoxin (0.125 mg,once daily). Functional capacity of the patients was determined by a6-minute walk test (6MWT), followed by an assessment of dyspnea usingthe Borg scale. The 6MWT was performed at 1 week, 1 month, 2 months, and3 months following the PADN procedure. The WHO classification at restand during exercise was recorded by a physician who was blinded to thestudy design.

Echocardiography was performed at 1 week, 1 month, 2 months, and 3months following the procedure. Echocardiographic studies were doneusing a Vivid 7 ultrasound system with a standard imaging transducer(General Electric Co., Easton Turnpike, Conn., US). All of theechocardiograms were performed and interpreted in the Medical UniversityEchocardiographic Laboratory. All of the measurements were performedfollowing the recommendations of the American Society ofEchocardiography. Digital echocardiographic data that contained aminimum of 3 consecutive beats (or 5 beats in cases of atrialfibrillation) were acquired and stored. RV systolic pressure is equal tosystolic PAP in the absence of pulmonary stenosis. Systolic PAP is equalto the sum of right atrial (RA) pressure and the RV to RA pressuregradient during systole. RA pressure was estimated based on theechocardiographic features of the inferior vena cava and assigned astandard value. The RV to RA pressure gradient was calculated as 4v_(t)² using the modified Bernoulli equation, where v_(t) is the velocity ofthe tricuspid regurgitation jet in m/s. The mean PAP was estimatedaccording to the velocity of the pulmonary regurgitation jet in m/s. Thetricuspid excursion index (TEI) is defined as (A-B)/B, where A is thetime interval between the end and the onset of tricuspid annulardiastolic velocity, and B is the duration of tricuspid annular systolicvelocity (or the RV ejection time). PA compliance for patients wascalculated as stroke volume divided by pulse pressure (systolic PAPminus diastolic PAP).

Hemodynamic measurements and blood oxygen pressure/saturationdeterminations from the RA, RV, and PA were done prior to andimmediately after the PADN procedure. These measurements were repeatedat 24 hours and 3 months.

A 7F flow-directed Swan-Ganz catheter (131HF 7, Baxter Healthcare Corp.,Irvine, Calif.) was inserted into an internal jugular or subclavianvein. Measurements of resting RA pressure, RV pressure,systolic/diastolic/mean PAP, pulmonary artery occlusive pressure (PAOP),cardiac output (CO) (using thermodilution method), and mixed venousoxygen saturation were recorded. The PVR [=(mean PAP-PAOP)/CO] andtrans-pulmonary gradient (TPG=mean PAP-PAOP) were then calculated. Allof the measurements were recorded at the end of expiration. Fivecriteria were used to evaluate if a PAOP measurement was valid: (1) thePAOP was less than the diastolic PAP; (2) the tracing was comparable tothe atrial pressure waveform; (3) the fluoroscopic image exhibited astationary catheter following inflation; (4) free flow was presentwithin the catheter (flush test); and (5) highly oxygenated blood(capillary) was obtained from the distal portion in the occlusionposition. If the PAOP measurement was unreliable, the left ventricularend-diastolic pressure was then measured and used rather than the PAOP.The blood samples from the SVC and pulmonary artery were obtained forthe measurements of oxygen pressure and saturation. Particularlysignificant reductions in systolic and mean PAP were achieved usingtemperatures above 50° C., drawing an electrical load of 8-10 W for aduration of 60-120 s, for example as shown in FIG. 14B.

The PADN procedure was performed with a dedicated 7.5 Fmultiple-function (temperature-sensor and ablation) catheter whichcomprised two parts, a catheter shaft 3 and handle 2 (FIG. 15A) which isan embodiment of the catheter illustrated in FIGS. 1-4. The catheter ofFIG. 15A had a tapered (to 5 F) annular ring 4 with 10 pre-mountedelectrodes 5 (E1-E10) each separated by 2 mm, however, other spacingscan also be used. For purposes of the description set forth below, theelectrodes 5 have been numbered, as shown in FIG. 15B, with thedistal-most electrode 5 identified as electrode E1 and the proximal-mostelectrode 5 identified as electrode E10.

As described above with reference to FIGS. 1-4, the annular ring 4 or(“circular tip”) can be constructed so as to be biased into anannular/circular shape, such as the circular shape illustrated in FIG.15B and FIG. 1 to have any desired outer diameter. For example, invarious embodiments, the annular ring 4 can be configured to be biasedinto a circular shape having an outer diameter of 20 mm, 25 mm, 30 mm,35 mm, 40 mm, 45 mm, or other diameters. Additionally, a kit containingthe catheter of FIG. 1 can include a plurality of different annularrings 4 configured to be biased to a plurality of different outerdiameters, such as those noted above, or other diameters.

A controller or “connect box” can be connected to the handle 2 of thecatheter for providing ablation energy. For example, an ablationcontroller 100 can be configured to provide ablation energy to each ofthe electrodes E1-E10. Thus, in some embodiments, the controller 100includes a selector knob 102 configured to allow a user to selectactivation of all the electrodes E1-E10, or selective actuation ofindividual ones of the electrodes E1-E10, one at a time.

Thus, in some embodiments, as illustrated in FIG. 15D, the selector knob102 includes a position indicator 104 which, by rotating the knob 102can be aligned with indicia corresponding to the electrodes E1-E10. Inthe illustrated embodiment, the indicia on the controller 100 includesthe numbers 1-10 as well as a position identified as “OFF” and aposition identified as “NULL.” In some embodiments, the connect cable106 can include a plurality of wires, for example, ten wires whichcorrespond to the lead wire 6 described above with reference to FIGS.1-4, each one of which is individually connected to respectiveelectrodes E1-E10.

The controller 100 can include a physical switch for creating anelectrical connection between a source of RF energy and a desired one ofthe electrodes E1-E10. An electrode (not shown) can be directlyconnected to the knob 102 with additional contacts (not shown) disposedaround the electrode at approximately the positions identified as 1through 10 on the controller 100. Thus, rotation of the knob 102 willconnect an internal electrode (not shown) with the contacts aligned witheach one of the positions 1-10.

The controller 100 can be configured to provide the desired amount ofablation energy when a circuit is created by the alignment of theposition indicator 104 with the corresponding position (1 through 10) onthe controller 100 thereby delivering electrical energy to the selectedone of the electrodes E1-E10 causing electrical energy to pass throughthe selected electrode 5 into any conductive material in contact withthat selected electrode.

For example, during the PADN procedure, the electrodes E1-E10 can be incontact with an inner wall of the pulmonary artery trunk therebyallowing electrical energy from one of the electrodes E1-E10 to flowthrough the tissue of the inner wall of the pulmonary artery, describedin greater detail below.

In some embodiments, with continued reference to FIG. 15D, thecontroller 100 can include a plurality of ports. For example, thecontroller 100 can include a catheter port 120, which can be configuredfor creating a fluidic connection to the annular ring for purposes ofproviding a flow of saline to the annular ring 4. The controller 100 canalso include an RF port 122 configured to connect to any knownradiofrequency generator used with regard to ablation procedures.

Additionally, the controller 100 can include an “ECG” port 124configured for connection with standard ECG monitoring equipment. Thus,in some embodiments, the connect cable 106 can also include wires orconduits for transmitting data through the RF port 124.

Thus, in some configurations, the RF port 122 can be connected to asource of RF energy (not shown). One or more wires (not shown) canconnect the port 122 to a contact on the end of an electrode connectedto the selector knob 102. Additionally, the ten wires (not shown) can beconfigured to deliver RF electrical energy to the electrodes E1-E10 eachof which can be connected to contacts (not shown) associated with theselector positions 1-10 disposed around the periphery of the selectorknob 102.

Thus, the electrode connected to the rotating selector knob 102 can bemoved into contact with the electrical contacts associated with each ofthe positions 1-10 thereby creating a circuit connecting the electricalenergy entering the controller 100 through the port 122 with theassociated lead wire 6 for conducting electrical energy to the desiredelectrode E1-E10.

Thus, specifically, when the selector knob 102 is turned such that theposition indicator 104 is aligned with position 1 on the controller 100,electrical energy from the RF port 122 is conducted through anassociated lead wire 6 to the electrode E1. Aligning the indicator 104with the other positions on the controller 100 would conduct electricalenergy to the other electrodes associated with those other positions.

In some embodiments, a method for treating pulmonary hypertension caninclude a step of identifying the position of the pulmonary trunk of thepatient using angiography. For example, baseline pulmonary arteryangiography can be performed to identify the position of the pulmonaryartery bifurcation from the main pulmonary artery into the left andright pulmonary arteries.

Additionally, the baseline pulmonary artery angiography can be used todetermine the diameter of the portions of the pulmonary artery trunkupon which ablation is desired. As such, the appropriate diameter of theannular ring 4 can be determined based on the determined diameters ofthe pulmonary artery trunk noted above. For example, in someembodiments, an annular ring 4 having a biased diameter slightly largerthan the diameters of the targeted anatomy can be used so as to enhancethe contact between the electrodes 5 and the inner surface of thetargeted anatomy. As such, for example, when the annular ring 4 is movedout of a sheath 1602 and allowed to expand into its biasedcircumferential configuration which has an outer diameter slightlylarger than the inner diameter of the targeted portions of the pulmonaryartery trunk, the bias of the annular ring 4 will assist in pressing theelectrodes 5 into contact with the targeted tissue.

In some embodiments, with reference to FIGS. 16A-16H, a method caninclude a step of positioning a catheter in a pulmonary artery trunk.For example, the sheath 1602 can be inserted through the femoral veinand advanced to the main pulmonary artery, as shown in FIG. 16A. Acatheter, such as the catheter illustrated in FIG. 1 and FIGS. 15A-15Ecan be advanced along the sheath 1602 shown in FIG. 16A to the locationof the pulmonary artery trunk.

With the distal end of the catheter maintained in place, the sheath 1602can be withdrawn. It may be necessary to push on the catheter tomaintain its position with the portion of the catheter forming theannular ring 4 held within the pulmonary artery trunk.

As the annular ring 4 is released from the sheath 1602, as illustratedin FIG. 16B, the annular ring 4 can adopt the shape and diameter towhich it is biased.

By slightly rotating and pushing the handle 2 in a clockwise direction,the annular ring 4 can be positioned at the proximal portion of the leftpulmonary artery, such as at the ostium. In some embodiments, thisinitial position can be within a range of approximately 5 mm from theorifice of the left pulmonary artery or within a range of 2 mm, asillustrated in FIG. 16D.

By observing the orientation of the annular ring 4, the desired one orplurality of the electrodes E1-E10 can be selectively energized so as toperform ablation at the desired location on the interior surface of theleft pulmonary artery. For example, in some embodiments, it may be moreeffective to selectively ablate the posterior wall of the left pulmonaryartery, so as to achieve at least some sympathetic denervation of theleft pulmonary artery and the proximal portion thereof, such as within 2mm or 5 mm of the ostium of the left pulmonary artery.

The annular ring 4 can then be rotated, such as in the counterclockwisedirection, by rotating and withdrawing the handle 2 in order toreposition the annular ring 4 into the distal portion of the mainpulmonary artery such as at the bifurcation area. For example, in someembodiments, as illustrated in FIG. 16E, the annular ring 4 can bepositioned within about 5 mm of the bifurcation in the pulmonary arterytrunk. Ablation can then be performed using the desired one or pluralityof the electrodes E1-E10.

For example, positioned as such, the selected one or plurality ofelectrodes E1-E10 can be energized to achieve the desired sympatheticdenervation of the distal portion of the main pulmonary artery. In someembodiments, it may be desirable to perform ablation preferentially onthe anterior wall of the distal portion of the main pulmonary artery.

Additionally, further rotating and pushing the handle 2 can be performeduntil the annular ring 4 is positioned in the proximal portion of theright pulmonary artery, such as at the ostium. In some embodiments, thisposition can be within 5 mm of the ostium of the right pulmonary artery.Further, in some embodiments, this position can be within 2 mm of theostium of the right pulmonary artery.

With the annular ring 4 positioned as such, the desired one or pluralityof electrodes E1-E10 can be energized so as to achieve at least somesympathetic denervation in the proximal portion of the right pulmonaryartery. For example, in some embodiments, it may be beneficial to focuson the posterior wall of the right pulmonary artery.

In some embodiments, a method for treating pulmonary hypertension canalso include a step of confirming the appropriate contact between theelectrodes E1-E10 and the endovascular surface corresponding to thethree positions noted above. For example, in some embodiments, suchconfirmation can be performed by determining if there is strong manualresistance when attempting to rotate the handle 2. Additionally, it canbe determined if the annular ring 4 cannot be advanced distally,resulting in the deformation of the catheter as illustrated in FIG. 16Gor if there is ease in withdrawing proximally, resulting in thedeformation of the catheter illustrated in FIG. 16H. Additionally,confirmation can be performed using angiographic confirmation.

After the annular ring 4 is positioned as desired, such as in thepositions illustrated in FIG. 16D, FIG. 16E and FIG. 16F, at least oneof the electrodes E1-E10 can be energized so as to perform ablation. Forexample, in some embodiments, a method for treating pulmonaryhypertension can include the sequential energization of each of theelectrodes E1-E10.

Additionally, in some embodiments, a method for treating pulmonaryhypertension or for performing pulmonary denervation can include thestep of repositioning the annular ring 4 so as to shift the location ofthe electrodes E1-E10 and then repeating energization of all of theelectrodes E1-E10. As such, a more complete denervation of the entireinner surface of the associated vessel can be achieved.

In some embodiments, any desired energy levels or temperatures can beused for performing ablation using the electrodes E1-E10 noted above.For example, in some embodiments, ablation can be performed attemperatures above 50° C., drawing an electrical load of 8-10 W for aduration of 60-120 s. Additionally, in some embodiments, the method oftreatment of pulmonary hypertension or the method of sympatheticdenervation of the pulmonary artery can be performed with a patientanesthetized but conscious. Thus, any ablation procedure can be stoppedif the patient complained of intolerable chest pain.

In some embodiments, EKG and hemodynamic pressure can be monitored andcontinuously recorded throughout the method. In a study performed inaccordance with the description noted above, success was defined as areduction in the mean PAP>10 mmHg (as measured by the Swan-Ganzcatheter). During the study, there were no complications. Additionally,the patients were monitored in the Coronary Care Unit (CCU) for at least24 hours after the PADN procedure was performed.

For example, in some embodiments of methods disclosed herein, adedicated 7.5 F triple-function catheter (A) can be used, which caninclude a tapered annular ring 4 with 10 electrodes 5 (each has 0.75 mmelectrode-width and is separated by 2 mm, pre-mounted. Electrodes areconnected with a connect-cable 106 and a connect-box/controller 100.There are 10 positions of the knob 102 (FIG. 15D) on the surface ofcontroller 100, and each is associated with one of the electrodes E1-E10on the annular ring 4 of the ablation catheter. Sequential ablation canbe performed by turning the knob 102 as desired after the whole systemis set up. In certain embodiments, ablation is interrupted whileswitching ablation from one electrode to another.

In some embodiments of methods for performing pulmonary arterydenervation or methods for treating primary PAH ablation of the distalportion of the main pulmonary artery can be performed preferentially onthe anterior side thereof. For example, in some embodiments, as shown inFIG. 17A, ablation can be performed at the positions identified as M1,M2, M3, M4, and M5.

With a continued reference to FIG. 17A, the position identified as M1 isat the “6 o'clock” position in the distal portion of the main pulmonaryartery. The positions identified as M3 and M5 are the sites where theanterior wall of the main pulmonary artery connects to the left andright pulmonary arteries, respectively. The positions identified as M2and M4 correspond to the “5 o'clock” and the “7 o'clock” positions onthe anterior side of the distal portion of the main pulmonary artery.

In some embodiments, with reference to FIG. 17B, sympathetic denervationin the left and right pulmonary arteries can be performed,preferentially, at approximately the middle of the anterior wall of theproximal portion of the left pulmonary artery (L1) and at approximatelythe upper conjunctive site of the distal portion of the main pulmonaryartery in the left pulmonary artery (L2).

Similarly, during a method of performing pulmonary denervation of theright pulmonary artery, ablation can be preferentially performed at apoint approximately at the middle anterior wall of the proximal portionof the right pulmonary artery (L3) and at approximately the upperconjunctive site of the distal portion of the main pulmonary artery andthe right pulmonary artery (L4).

In some embodiments, sympathetic denervation can be performed, forexample, for treatment of pulmonary hypertension associated with apulmonary duct artery (PDA) 1802. For example, a pulmonary duct arteryusually connects the descending aorta with the left pulmonary artery504, as shown in FIG. 5. With this anatomy, the left pulmonary arterycan be significantly larger than the right pulmonary artery.

Thus, in some embodiments, ablation can be performed at a positionproximal to connection between the left pulmonary artery and thepulmonary duct artery, identified as “Level A” in FIG. 18A. Thus, usingthe technique described above with reference to FIGS. 16A- 16H, theannular ring 4 can be positioned at a position corresponding to “LevelA” of FIG. 18B. Ablation can then be performed around part or all of theinterior wall of the left pulmonary artery at that location.

In some embodiments, ablation can be preferentially performed on theanterior wall of the left pulmonary artery proximal to the proximal endof the pulmonary duct artery. For example, ablation can be performed atfour or more sites, such as those identified as sites L11, L12, L13,L14. As illustrated in FIG. 18B, position L11 corresponds to “12o'clock”, position L12 corresponds to “2 o'clock”, position L13corresponds to “3 o'clock”, and position L14 corresponds to “6 o'clock.”Other positions can also be used.

Additionally, in some embodiments, ablation can also be performed atpositions M1-M5 illustrated in FIG. 17A and positions L1-L4 of FIG. 17B.

In some embodiments, a method for sympathetic denervation can be usedfor treating pulmonary hypertension resulting from unilateral chronicthrombotic embolism. For example, a patient suffering from unilateralCTEH can have an occluded right pulmonary artery. For example, in somepatients, the RPA can be significantly enlarged as illustrated on theleft side of FIG. 19A. Similarly to the method described above withreference to FIG. 18B, ablation can be performed at the positionidentified as “Level B” in FIG. 19A. Ablation can be performed at one ora plurality of locations along the inner surface of the right pulmonaryartery at the position of Level B, or other positions. Additionally,ablation can be preferentially performed on a plurality of points alongthe anterior wall of the right pulmonary artery at the position of LevelB.

For example, the positions identified in FIG. 19B can be considered suchas position L21 corresponding to “12 o'clock”, position L22corresponding to “2 o'clock”, position L23 corresponding to “3 o'clock”,and position L 24 corresponding to “6 o'clock.” Additionally, in someembodiments, ablation can also be performed at positions M1-M5illustrated in FIG. 17A and positions L1 and L2 illustrated in FIG. 17B.

With reference to FIG. 20, further embodiments of treatments forpulmonary hypertension can include selected ablation of portions of thepulmonary artery trunk, at fewer ablation sites than some of theembodiments described above. For example, FIG. 20 identifies “Level C”for reference with regard to the ablation sites identified in FIG. 21.

With reference to FIG. 21, an enlarged schematic diagram of “Level C”identified in FIG. 20 identifies a plurality of that ablation sites, b₁,b₂, b₃ which are grouped in a portion of the pulmonary artery trunkproximal to a left side lateral wall at the upper end of the mainpulmonary artery and proximal to a lower wall of the proximal portion ofthe left pulmonary artery, where those portions meet. For example, asillustrated in FIG. 21, the ablation site b₁ is disposed atapproximately a left lateral apex of the distal end of the mainpulmonary artery, which connects with a lower wall of the proximal endof the left pulmonary artery. Additionally, the ablation sites b₂, b₃are disposed, along or substantially along the “Level C” identified inFIG. 20, on the anterior and posterior sides, respectively, of theablation site b₁. These ablation sites b₁, b₂, and b₃ may be targeted toablate a particular bundled cluster of sympathetical nerves on the leftlateral side of the distal end of the main pulmonary artery. Thesebundled clusters may be approximately 5 mm above the pulmonary valve 514(FIG. 5) but under the carina 602 (FIG. 6).

FIG. 22A illustrates a further embodiment of the annular ring 4illustrated and described above with reference to FIG. 1 and FIG. 15B.The embodiment of the annular ring 4 illustrated in FIG. 22A isidentified with the reference 204. The annular ring 204 illustrated inFIG. 22A can be constructed in accordance with the description set forthabove with regard to the annular ring 4 and can be used with thehandheld device 1 (FIG. 1), except with regard to the differencesdescribed below.

As shown in FIG. 22A, the annular ring 204 can have a fewer number ofelectrodes than that included in the annular ring 4 described above. Inthe illustrated embodiment, the annular ring 204 includes fiveelectrodes, 200, 205, 206, 208, 210. Additionally, the annular ring 204is provided with and configured to conform to (or be biased to) an ovalshape, when in its deployed/relaxed state. In its deployed/relaxedstate, the annular ring 204 may be substantially planar. Also, in itsdeployed/relaxed state, the annular ring 204 may be substantiallyorthogonal, and optionally perpendicular, to a portion of the flexibleend 3 of the catheter body connected with the annular ring 204. Asillustrated in FIG. 22A, in its deployed state, the annular ring 204 canhave a diameter D₁ along its major axis. The diameter D₁ is larger thanthe second diameter D₂ along the minor axis of the annular ring 204.Such a configuration provides the angular ring 204 with an oval shape,when in its deployed state. The electrodes 200, 205, 206, 208, 210 ofthe annular ring 204 can be sized in space with the dimensionsidentified in FIG. 22A, or other dimensions. Also, in certainembodiments, the annular ring 204 may be elliptical and optionallysubstantially planar. Optionally, such an elliptical ring can be lessthan a complete loop. For example, the distal end of the annular ring204 may not curve 360 degrees back to the proximal end of the annularring but may curve around by an angle of less than 360 degrees (forexample by curving at an angle of 270 degrees to 359 degrees). Incertain embodiments, the proximal end of the annular ring may beseparated by a distance of 3 mm as illustrated in FIG. 22A due to notcurving 360 degrees back to the proximal end of the annular ring 204.

With continued reference to FIG. 22A, the electrodes 206, 205, 208 canbe arranged and sized to provide for selective ablation of a pulmonaryartery corresponding to the ablation sites b₁, b₂, b₃ described abovewith reference to FIG. 21. Further, the electrodes 206, 205, 208 canhave different sizes. In some embodiments, the electrode 206, configuredand sized to accommodate denervation of the site b₁ can be larger thanthe electrodes 205, 208. Further, in some embodiments, the electrode 205can be larger than the electrode 208. For example, the electrode 206 forablation at b₁ may be 4 mm long while the electrode 205 for ablation atb₂ may be 3 mm long and the electrode 208 for ablation at b₃ may be 2 mmlong. Other arrangements, configurations, and sizes can also be used.The electrode 206, for ablation at b₁, may be located at an end ofdiameter D₁ and/or straddle an apex of the major axis of annular ring204.

With continued reference to FIG. 22A, the annular ring 204 can beconstructed with several sizes. For example, FIG. 22A includes examplesof diameters D₁, D₂ that can be used for five different sizes of theannular ring 204. The diameters D₁, D₂ for those five different sizescan be combined in the following listed pairs of diameters (inmillimeters), which are listed in the format (D₁, D₂): (25, 20), (30,25), (35, 30), (40, 35), and (50, 45). Thus, in some embodiments, thediameter D₁ is 5 mm larger than the diameter D₂. Other sizes andproportions can also be used.

It has been noted that in at least some patients, the sympatheticenervation of the pulmonary arteries (PAs) is concentrated mostly aboutthe left proximal PA. There can be relatively less sympatheticenervation of the right PA. The vagus nerve can travel deep (from the PAperspective) to the sympathetic nerves.

In some embodiments, as noted above, effective reduction of PAhypertension (PAH) can be achieved by ablating at 3 sites in the leftside only, such as approximately at the locations b₁, b₂, b₃ identifiedabove with reference to FIG. 21. Additional ablations can be omitted.Thus, in some embodiments, ablations can be carried out at or in thevicinity of the ablations locations b₁, b₂, b₃ and further ablations beavoided or omitted.

FIG. 22B illustrates a further embodiment of the annular ring 204illustrated and described above with reference to FIG. 22A. Theembodiment of the annular ring 204 illustrated in FIG. 22B is identifiedwith the reference 220.

As illustrated in FIG. 22B, in its deployed state, the annular ring 220can have a diameter D₃ along its major axis. The diameter D₃ is largerthan the second diameter D₄ along the minor axis of the annular ring220. Such a configuration provides the angular ring 220 with an ovalshape, when in its deployed state. For example, FIG. 22B includesexamples of diameters D₃, D₄ that can be used for five different sizesof the annular ring 220. The diameters D₃, D₄ for those five differentsizes can be combined in the following listed pairs of diameters (inmillimeters), which are listed in the format (D₃, D₄): (25, 20), (30,25), (35, 30), (40, 35), and (50, 45). Thus, in some embodiments, thediameter D₃ is 5 mm larger than the diameter D₄. Other sizes andproportions can also be used.

The annular ring 220 may be configured for the ablation of three siteswith electrodes 206, 205, and 208 at approximately at the locations b₁,b₂, b₃ identified above with reference to FIG. 21 and FIG. 22A. Theelectrode 206, for ablation at b₁, may be located at an end of diameterD₃ and/or straddle an apex of the major axis of annular ring 220. Theelectrodes 208, 206, and 205 of the annular ring 220 can be sized inspace with the dimensions identified in FIG. 22A, or other dimensions.

In some embodiments, the tissue temperature is raised to 50° C., (range)48°- 52°), for example, by applying RF energy to each of the 3 sites b₁,b₂, b₃ for 2 minutes each. As noted above, optionally, additionalablations can be omitted.

The generator can be configured to, and can be operated to, deliver 3-15watts of RF energy. In some embodiments, it has been observed that animmediate decrease in PA blood pressure of at least about 10% can beachieved by ablating the three sites b₁, b₂, b₃ as described above. Sucha physiological change can serve as immediate feedback and can be usedto further guide treatment.

In some animals, visualization of the sympathetic nerves shows thinningof the axons following RF ablation. In humans with PAH and in animals(treated with MCHT to produce PAH experimentally), there is evidence ofvascular remodeling 3 months post treatment, with some resolution of HTNinduced wall thickening. For some patients, 1-2 years after treatment,the initial improvement in PAH note above persists for those intervalsfollowing treatment.

The efficacy of the PADN procedure versus standard pharmacotherapy forthe treatment of PAH with different etiologies was investigated in anadditional study. In the additional study, 28 patients with PAH wereassigned to standard medication and the PADN procedure sequentially. ThePADN procedure was associated with significant improvements in 6-minutewalk distance (6MWD) and hemodynamics six months following the PADNprocedure. Also, the PADN procedure had less frequent PAH-related eventsafter 6- to 12-month following the PADN procedure.

The additional study included a total of 28 patients (11 males and 17females, with an average age of 49 years). As described in Table, 1,there were 8 patients with IPAH, 9 with PH from LHD, 4 with connectivetissue disease, 3 with chronic thrombolitic PH and 4 with congenitalheart disease after surgical repairing. The mean time interval from thediagnosis of PAH/PH to the present study was 4.24 years. During wash-outperiod, there was 1 patient with LHD having the worsening of symptomneeded diuretic treatment.

TABLE 1 Baseline characteristics Variables Results Patient number, n 28Male, n (%) 11 (39.3) Age, yr 49 ± 17 Etiology, n (%) IPAH 11 (39.3) LHD 8 (28.6) CTD 2 (7.1) CTEPH  3 (10.7) CHDSR  4 (14.3) Time fromdiagnosis to enrolling, yr 4.24 ± 7.13 Presentation, n (%) Chest pain  8(28.6) Syncope  4 (14.3) Fatigue 27 (96.4) Dyspnea 27 (96.4) Medicationat screening, n (%) Diuretics 23 (82.1) Calcium-channel antagonist  4(14.3) Beta-blocker  8 (28.6) Prostacyclin 23 (82.1) 5′-PDE 10 (35.7) ETreceptor antagonist  5 (17.9) Digoxin 13 (46.4) IPAH, idiopathicpulmonary hypertension; LHD, left heart disease; CTD, connective tissuedisease; CTEPH, chronic thrombolytic pulmonary hypertension; CHDSR,congenital heart disease after surgical repair; 5′-PDE,phosphodiesterase type 5 inhibitor

Patients with a resting mean PAP (mPAP)≧25 mmHg with WHO functionalclass II-IV PAH were included in the additional study. Particularly, forthe patients with pulmonary hypertension (PH) secondary from left heartdisease (LED), additional requirements included a pulmonary vesselresistance (PVR)>2.5 woods unit and a pulmonary arterial obstructivepressure (PAOP)>15 mmHg at rest. None of the patients had activeinflammation or cancer. Also, none of the patients had PH secondary fromportable hypertension and drug or toxin exposure. The study protocol wasapproved by the Institute Research Board (Nanjing Medical University).

A wash-out consisting of 5 half-lives was performed for all thepatients. All the patients who met the above inclusion and exclusioncriteria were included and entered into the first wash-out period(defined as stopping all medications for at least 5 half-lives, with theexception of warfarin) as right heart catheterization and adenosine testfor all patients were not performed before study. Warfarin wascontinuously prescribed. Otherwise, aspirin (100 mg/d) and Plavix (75mg/d) were prescribed instead of warfarin for the patients who wereintolerable to warfarin. Immediately after the PADN procedure, thestandard medication for PAH were stopped for all the patients.

If the patients were taking multiple drugs, the longest half-lives ofany drug was selected. For example, for a patient who was takingbosentan (half-time <5 h) and digoxin (half-time=33 h), then thewash-out period would be 5×33 h=165 h (7 days). After the wash-outperiod, the drugs were prescribed again and continued for 6 months(Medication treatment). The selection of drugs was left to thephysician's discretion based on comprehensive analysis. After 6 months,the patients underwent a second wash-out period of 5half-lives in orderto establish the PADN procedure as a standard alone therapy.

For the PADN procedure, a 7 F flow-directed Swan-Ganz catheter (Edwards,USA) was inserted percutaneously in the patients who were under localanesthesia into an internal jugular vein for the measurements of theresting RAP, sRVP, sPAP, mPAP, PAOP, and cardiac output (CO) values. ThePVR [=(mPAP-PAOP)/CO] was then calculated. All the measurements wereperformed at the end of expiration. If the PAOP measurement wasunreliable, the left ventricular end-diastolic pressure was measured andused rather than the PAOP measurement. Two blood samples from the RA, RVand PA were obtained for the measurements of oxygen pressure andsaturation. If the difference between the oxygen pressure or saturationmeasurement of these two samples was >7%, further sampling was performedto identify the location of the left-to-right shunt.

The PADN procedure was performed at three sites around the conjunctionalarea between the distal main trunk and the ostial left branch. FIG. 23Aillustrates an anterior-posterior and cranial)(20°) view of pulmonaryarterial angiograph 2300. Specifically, the angiograph 2300 illustratesthe RPA 2302, MPA 2306 and LPA 2304 of a heart of one of the patients.FIG. 23B illustrates the angiograph of FIG. 23A with a line representingthe lateral wall of MPA 2320, a line 2318 representing the anterior wallof the LPA. The crossing site by these two lines 2312 and 2316 is thepoint 2310. The crossing site by a line 2314 representing the posteriorwall of LPA and the line 2320 representing a wall of the MPA is thepoint 2308 which is 1-2 mm posteriori to the point 2310. The line 2316starts from the inferior wall of RPA and ends at the point 2310, thepoint 2312 localizes at this level and 1-2 mm anteriorly to the point2310. FIG. 23C illustrates the angiograph of FIG. 23A with a catheterwith 10 electrodes is positioned at the distal MPA. In FIG. 23C,electrode 2332 matches with point 2310, electrode 2330 matches withpoint 2308 and electrode 2334 matches with point 2312. The followingablation parameters were programmed at each point: a temperature of 45°C.-50° C., energy <15 W, and a time of 120 s. The procedure would ceasefor 10 seconds if the patient felt intolerable chest pain during theprocedure. The EKG and pressure lines (including cardiac output) weremonitored and continuously recorded throughout the PADN procedure.

The patients were monitored in the CCU for at least 24 hours. Allmeasurements were repeated post-procedure, at 24 hours, at 3 months, at6 months, and at 12 months. Magnet resonance image (MRI) and CT scanningof the pulmonary artery were performed before the PADN procedure and at6 months after the PADN procedure.

The success of a PADN procedure was defined as the reduction of sPAP ormPAP immediately after the procedure or at 24 hour ≧10% compared to thebaseline values, without intra-procedural complications. The primaryendpoint of the additional study was the difference in 6MWD after the 6months between the medication and PADN procedure. The secondaryendpoints included composite and individual PAH-related events includingthe worsening of PAH, the initiation of treatment with the intravenousor subcutaneous injection of drugs, lung transplantation, atrialseptostomy or all-cause death. Repeat hospitalization also served as asecondary endpoint.

For assessing the 6MWD, baseline blood samples were obtained for theanalysis of N-terminal brain natriuretic peptide (NT-pro BNP) levelsprior to administering the 6MWD. The 6MWD, the Borg scale and the WHOfunctional class at rest and during exercise were estimated and recordedby a physician who was blinded to the study design. The 6MWD has beenselected as an endpoint in previous studies of PAH patients. Notably,the 6MWD in patients without PAH-related events was higher than that inpatients with PAH-related events, which suggests that a 15% reduction inthe 6MWD may be clinically meaningful. This result supports the use of a15% reduction in the 6MWD as a criterion for PAH worsening in clinicalstudies. Also, PAP, RAP and PVR are useful parameters correlated withthe prognosis of the PAH patients. A sPAP between 50-70 mmHg and RAP>8mmHg were markers indicating the severity of PAH disease. The 6MWDimprovement after the PADN procedure was paralleled by an improvement inRAP, sPAP and mPAP. However, a correlation between the PA hemodynamicsat baseline or post-medication with 6MWD was not established, mostlikely because the improvement of skeletal blood flow without a changein PA hemodynamics may also account for the improvement of 6MWD.

For the echocardiographic measurements, all echocardiograms wereperformed (Vivid 7, General Electric Co., Easton Turnpike, Conn., us)and interpreted in the Nanjing Echocardiographic Laboratory followingthe recommendations of the American Society of Echocardiography. Digitalechocardiographic data that contained a minimum of 3 consecutive beats(or 5 beats in cases of atrial fibrillation) were acquired and stored.RV systolic pressure (sRVP) is equal to systolic PAP (sPAP) in theabsence of pulmonary stenosis. sPAP is equal to the sum of right atrial(RA) pressure (RAP) and the RV to RA pressure gradient during systole.RAP was estimated based on the echocardiographic features of theinferior vena cava and was assigned a standard value. The RV to RApressure gradient was calculated as 4v_(t) ² using the modifiedBernoulli equation in which v_(t) is the velocity of the tricuspidregurgitation jet in m/s. mPAP was estimated according to the velocityof the pulmonary regurgitation jet in m/s. The tricuspid excursion index(Tei) is defined as (A-B)/B in which A is the time interval between theend and the onset of tricuspid annular diastolic velocity, and B is theduration of tricuspid annular systolic velocity (or the RV ejectiontime).

Table 2 provides data indicating how the 6MWD increased from 361±112 mto 373±111 m (p=0.009) after 6-month Medication treatment and from358±115 m to 423±98 m (p<0.001) 6-month after PADN procedure, in linewith the significant reduction of the NT-pro BNP and WHO functionalclass.

TABLE 2 Comparison of measurements before and after treatment Medication(n = 28) PADN (n = 28) Prior-to 6-month p Prior-to 6-month p NT-pro BNP,pg/ml 2293 ± 2741 1732 ± 1878 0.007 2669 ± 3178 1296 ± 947  0.015 WHOclass, point 2.75 ± 0.52 2.46 ± 0.58 0.009 2.75 ± 0.52 2.21 ± 0.63<0.001 6MWD, mm 361 ± 112 373 ± 111 0.009 358 ± 115 423 ± 98  <0.001Cardiac output  3.2 ± 0.94 3.26 ± 0.89 0.221 3.25 ± 1.05 3.91 ± 1.080.002 RHC sPAP, mmHg 91.9 ± 33.0 91.5 ± 33.4 0.485 91.9 ± 33.3 78.2 ±29.4 <0.001 mPAP, mmHg 56.1 ± 21.1 55.9 ± 21.2 0.762 56.7 ± 21.8 48.9 ±19.2 <0.001 PCWP, mmHg  13 ± 7.7 13.8 ± 6.9  0.365 12.5 ± 8.6  12.9 ±6.3  0.788 mRAP, mmHg 11.5 ± 4.2  11.8 ± 4.6  0.442 11.4 ± 4.7  8.8 ±3.4 0.001 sRVP, mmHg 89.3 ± 31.2 91.3 ± 32.1 0.255 89.3 ± 31.6 83.0 ±34.7 0.147 PVR, woods unit 13.8 ± 7.6  13.6 ± 6.9  0.721 14.3 ± 8.6  9.7± 6.8 0.002 Cardiac echo mPAP, mmHg 47.9 ± 24.2 45.6 ± 23.2 <0.001 47.4± 24.8 38.1 ± 16.5 0.002 mRAP, mmHg 11.8 ± 3.1  11.1 ± 2.8  0.043 11.8 ±3.1  8.9 ± 3.1 <0.001 sRVP, mmHg 96.0 ± 87.9 87.9 ± 26.9 <0.001 96.1 ±31.7 78.6 ± 23.3 <0.001 sPAP, mmHg 98.1 ± 29.5 87.2 ± 25.2 <0.001 98.2 ±32.2 79.9 ± 24.6 <0.001 Pericardial fluid, mm 1.11 ± 1.64 1.43 ± 1.930.059 1.96 ± 2.89 0.85 ± 0.89 0.002 RV Tei, % 0.59 ± 0.17 0.55 ± 0.160.029 0.69 ± 0.09 0.36 ± 0.09 <0.001 PADN, pulmonary artery denervation;NT-pro BNP, N terminal-pro brain natriuretic peptide; 6MWD, 6-minutewalk distance; RHC, right heart catheterization; sPAP, systolicpulmonary arterial pressure; mPAP, mean pulmonary arterial pressure;mRAP, mean right atrial pressure; sRVP, systolic right ventricularpressure; PVR, pulmonary vessel resistance;

There was a significant difference in the increase in 6MWD at the6-month follow-up between the Medication (13±24 m) and the PADNprocedure (65±85 m) (95% CI: −21.34˜−3.49, p=0.002), coupled with thesignificant improvement of hemodynamic after PADN procedure. The PADNprocedure was associated with less frequent PAH-related events at the6-month (10.8%) and 12-month (17.9%) follow-up, compared to 42.9% after6-month Medication treatment (all p<0.05). As illustrated in Table 3 andFIG. 24A, the A 6MWD (defined as the 6MWD at the 6-month follow-up minusthe baseline 6MWD) was +13±24 m (+3.9% increase) in the Medicationtreatment, which was significantly different to the +65±85 m (+23.9%increase, 95% CI: −21.34˜−3.49, p=0.002) at the 6-month and +95±61 m(+34.9% increase) at one-year after the PADN procedure.

TABLE 3 Comparison of the differences in measurements after 6-monthtreatments Medication PADN (n = 28) (n = 28) 95% CI p NT-pro BNP, pg/ml −562 ± 1009 −1373 ± 2792 −42.84~1665.44 0.062 WHO functional class−0.36 ± 0.49 −0.54 ± 0.58 −0.10~0.46  0.202 6MWD, m  13 ± 24  65 ± 85−21.34~3.49    0.002 % of increase +3.9% 23.9% −0.31~0.09  0.001 Cardiacoutput  0.06 ± 0.24  0.67 ± 1.05 −0.10~0.20  0.005 RHC sPAP, mmHg −0.46± 3.47 −13.75 ± 14.1  8.38~18.19 <0.001 mPAP, mmHg −0.14 ± 2.48 −7.86 ±6.10 5.26~10.18 <0.001 PCWP, mmHg  0.82 ± 4.72  0.36 ± 6.96 −1.63~2.56 0.653 mRAP, mmHg −0.21 ± 2.62 −2.53 ± 3.75 0.70~3.93  0.007 sRVP, mmHg 1.96 ± 8.93  −6.22 ± 22.07 1.76~14.62 0.014 PVR, woods unit −0.17 ±2.56 −4.59 ± 7.06 1.99~6.83  0.001 Cardiac echo mPAP, mmHg −2.36 ± 2.78 −9.28 ± 13.93 1.98~11.86 0.008 mRAP, mmHg −0.54 ± 1.57 −2.86 ± 2.861.20~3.44  <0.001 sRVP, mmHg −8.07 ± 9.73 −17.54 ± 16.97 4.78~14.15<0.001 sPAP, mmHg −10.89 ± 11.87 −18.25 ± 16.73 3.13~11.58 0.001Pericardial fluid, mm  0.11 ± 0.93 −0.74 ± 2.63 −1.04~2.47  0.036 RVTei, % −0.04 ± 0.09 −0.34 ± 0.11 0.24~0.35  <0.001 CI, confidenceinterval; PADN, pulmonary artery denervation; NT-pro BNP, N terminal-probrain natriuretic peptide; 6MWD, 6-minute walk distance; RHC, rightheart catheterization; sPAP, systolic pulmonary arterial pressure; mPAP,mean pulmonary arterial pressure; mRAP, mean right atrial pressure;sRVP, systolic right ventricular pressure; PVR, pulmonary vesselresistance;

In the Medication treatment, there were 9 patients (32%) whose 6MWDdecreased (range from −6m to −47m) after the 6-month treatment. Of those9 patients, 5 patients had an average 6MWD increase of 45 m 6-monthafter the PADN procedure, whereas no change was observed in 4 patients.Among those 4 patients, there was still no change 6MWD in 1 patient atone-year after the PADN procedure. Finally, there were 2 patients whohad no change in 6MWD at one-year follow-up after PADN procedure. Asillustrated in FIG. 24B, the 6MWD after the PADN procedure rather thanMedication treatment was negatively correlated with mPAP (r=−0.416,p=0.028) and sPAP (r=−0.401, p=0.034).

The study also demonstrated improvement of hemodynamic and cardiacfunction. The Δ mPAP and ΔCO at 6-month after the PADN procedure weregreater than those in the Medication treatment (−7.86±6.10 mmHg vs.−0.14±2.48 mmHg, P<0.001; 0.67±1.05 L/min/1.73 m2 vs. 0.06±0.24 L/min/1.73 m2, p=0.005, Table 3), with resultant significant differences inthe reduction of the pericardial fluid amount (−0.74±2.63 mm vs.+0.11±0.93 mm, p=0.036) and Tei (−0.34±0.11 points vs. −0.04±0.09points, p<0.001). As illustrated in FIG. 24C, these improvements weresustained through one-year follow-up after PADN procedure.

Table 4 illustrates how, after the 6-month treatment, a PAH-relatedevent was observed in 12 patients ( 42.9%) in the Medication treatmentand 3 patients ( 10.8%) in the PADN procedure (p=0.002). These eventswere mainly driven by the worsening of PAH.

TABLE 4 Clinical follow-up after the 6-month treatments Medication PADN(n = 28) (n = 28) p PAH-event, n (%) 12 (42.9) 3 (10.8) 0.002 All-causedeath 0 0 Atrial septostomy 0 0 Lung transplantation 0 0 Needing IV & IS2 (7.2) 0 Worsening of PAH 10 (36.0) 3 (10.8) Re-hospitalization, n (%)12 (38.3) 4 (14.4) 0.018 Cost, ×10,000 USD/per pt 3.5 ± 1.2 0.6 ± 0.7<0.001 Any-cause Death, n (%) 0 0 Access site hematoma, n (%) 0 0Aneurysm, n (%) 0 0 Thrombus, n (%) 0 0 PADN, pulmonary arterydenervation; PAH, pulmonary arterial hypertension; pt, patient;

The mean time from treatment to clinical worsening was 125 days (rangeof 22 to 166 days) in the Medication treatment, which was significantlyshorter than the 166 days (range from 47 to 172 days) reported in thePADN procedure (p=0.01). Re-hospitalization was required in 42.9% of thepatients in the Medication compared to 14.4% of the patients in the PADNprocedure (as described when p=0.018 in Table 4). There were no accesshematomas, aneurysms, thrombus formations or any-cause deaths after the6-month treatment.

The A 6MWD was approximately +60 m after PADN procedure and +15 m afterthe medication treatment. A total of 28 patients were required toachieve significance (2-sided p-value, 80% power). The difference ineach variable (at the 6-month period minus the baseline) for eachtreatment was calculated and compared between the two treatments. Thecontinuous variables were expressed as the mean ±SD. A normality testfor all the continuous variables was performed using theKolmogorov-Smirnov and Shapiro-Wilk tests. The differences in thecontinuous variables between the two treatments were analyzed using apaired t-test or the Mann-Whitney U test when appropriate. Thecategorical variables were compared using Fisher's exact test. Theevent-free survival rate was generated using the Kaplan-Meier method andwas analyzed with the log-rank test. Statistical significance wasdefined as a two-sided P value <0.05. All the analyses were performedusing the statistical program SPSS 19.0 (SPSS Institute Inc., Chicago,Ill., USA).

For the additional study, a worsening of PAH was defined as theoccurrence of all three of the following measurements: a decrease in the6MWD of at least 15% from baseline, confirmed by a second 6MWD performedon a different day within 14 days of the first measurement; a worseningof the symptoms of PAH; and the need for additional treatment for PAH. Aworsening of the symptoms of PAH was defined as any of the followingmeasurements: a change from baseline to a higher WHO functional class(or no change in patients who were in WHO functional class IV atbaseline) and the appearance or worsening of signs of right heartfailure, which did not respond to oral diuretic therapy. An independentclinical event committee adjudicated, in a blind fashion, all the eventsrelated to PAH and all the deaths that were reported up to the end ofthe treatment.

At the one-year follow-up, there were 5 (17.9%) PAH-related events (2new events, including 2 sudden deaths). The 6MWD in patients withoutPAH-related events was 467±100 m, which was higher than the 393±42 mreported in patients who had experienced an event (p=0.018).Accordingly, patients with 6MWD<400 m had higher rate of PAH-relatedevent ( 44.4%) at one-year after the PADN procedure, compared 5.3% inpatients with 6MWD≧400 m (p=0.010).

Therefore, the additional study indicated that the PADN procedure wasassociated with a significant improvements in 6MWD and hemodynamics at6-month, with resultant less PAH-related events. For example, the PADNprocedure led to a greater improvement of pulmonary arterialhemodynamics with subsequently less frequent PAH-related events andre-hospitalizations.

FIGS. 25A-25H are various views of a digital ablation controller 2500that can be used in lieu of the controller 100 illustrated in FIGS.15C-15D. Similar to the controller 100, the digital ablation controller2500 can be connected to the handle 2 of the catheter for providingablation energy. For example, the digital ablation controller 2500 canbe configured to provide ablation energy and control the electrodesE1-E10 of FIG. 15B.

Generally described, the digital ablation controller 2500 provides for asingle, portable housing for both control and feedback duringperformance of the PADN procedure. The digital ablation controller 2500may control the amount of power provided to the electrodes 5 from apower source (such as a battery or a power grid) such that the amount ofpower is within nominal limits for ablation. Also, the digital ablationcontroller 2500 may enable the storage and retrieval of various patientprofiles that may include different configuration settings for catheterconfiguration and/or provision of power to the electrodes of thecatheter.

For example, different patient profiles may include different settingsfor which the PADN procedure is to be performed with different settingsfor different electrodes. Also, the digital ablation controller 2500 mayinclude a user interface from which a user or operator of the digitalablation controller may provide manual control and/or enter or retrieveinformation from the patient profiles.

For example, the user interface may include information on theoperational characteristics of the electrodes (such as ablationtemperature and time captured by the catheter's sensors) and the user oroperator of the digital ablation controller may perform the PADNprocedure based upon the operational characteristics of the electrodes.Also, the user or operator of the digital ablation controller maydirectly select a particular electrode (or electrodes) to activate forablation from the user interface. Thereby, the digital ablationcontroller would direct power (such as power from the battery) to theappropriate electrode(s) selected via the user interface.

In certain embodiments, the digital ablation controller may provideautomatic control of the PADN procedure based upon feedback from sensorson the catheter. For example, the operational characteristics of theelectrodes may be captured by the catheter's sensors and used toregulate aspects of the PADN procedure (such as the amount of timeablation is performed at a particular location based upon the temperateat the location of ablation).

In certain embodiments, the digital ablation controller includes abattery configured to store power at a level sufficient for ablationusing one or more electrodes 5 of the multi-pole synchronous pulmonaryartery radiofrequency ablation catheter. By directly using the battery,the provision of power to the electrodes is contingent upon stored powerrather than power provided ad hoc to the electrodes, such as from powerprovided by a local power grid. Thereby, the availability of power isnot contingent upon power being readily available to the digitalablation controller but rather the digital ablation controller mayfunction independent of the local power grid so long as the battery issufficiently charged.

FIG. 25A illustrates a top perspective view of the digital ablationcontroller 2500 in a closed position. The top perspective viewillustrates the power cord 2504 connected to the digital ablationcontroller 2500. As illustrated, the digital ablation controller 2500may be a single housing configured to provide an interface for controland power for the multi-pole synchronous pulmonary artery radiofrequencyablation catheter. For example, the digital ablation controller 2500 mayreceive and store power such that the PADN procedure may be performedusing the stored (battery) power in the digital ablation controller2500. Also, the digital ablation controller 2500 may provide preciseregulation of power by digitally controlling different aspects of thePADN procedure, such as the particular electrode(s) used for ablation,the power at any particular electrode and the time for ablation. Thedigital ablation controller 2500 may also provide real time feedbackfrom sensors (such as temperature sensors and/or impedance sensors)disposed at various points on the multi-pole synchronous pulmonaryartery radiofrequency ablation catheter (such as at the locations of theelectrodes), as discussed in FIGS. 1-4.

FIG. 25B illustrates a top perspective view of the digital ablationcontroller 2500 in an open position. The user interface 2512 is visibleand usable in the open position of the digital ablation controller 2500.Also, a carrying handle 2510 is illustrated on the digital ablationcontroller 2500. FIG. 25C illustrates a back perspective view of thedigital ablation controller 2500 in the open position.

FIG. 25D is a screen shot of an initial user interface 2526 of thedigital ablation controller 2500. The initial user interface includesbuttons that may be selected to interact with the digital ablationcontroller 2500. For example, the initial user interface 2526illustrates a button 2520 for changing a language setting of the userinterface 2520, a button 2522 to access data stored in the digitalablation controller 2500 and a button 2524 to begin operation of thedigital ablation controller 2500.

FIG. 25E is a screen shot of the user interface 2530 presenting optionsfor entering patient information for performance of the PADN procedure.The user interface includes a button 2532 to begin browsing existingpatient profiles stored in the digital ablation controller 2500. Theuser interface also includes sections 2534 for inputting information fora new patient profile, such as a patient's name, identification number,age, sex and the selection of various preset operational settings forthe digital ablation controller 2500. The user interface also includes asection 2536 to input remarks concerning the patient for the patientprofile.

FIG. 25F is a screen shot of a user interface 2540 of the digitalablation controller 2500 at the initiation of the PADN procedure. Theuser interface 2540 includes information concerning the power level2542, time 2544, temperature 2546 and impedance 2548 of the electrodesof the catheter. The user interface also includes buttons from which aparticular electrode 5 on the annular ring 4 may be selected foractivation.

FIG. 25G is a screen shot of a user interface 2550 of the digitalablation controller 2500 during operation. Ablation may be initiated byselecting a button for a particular electrode, such as a button 2570associated with electrode 2572 designated with the number “2”highlighted on the user interface. The operational relationship of theelectrode 2572 between impedance, power and temperature over time isdisplayed on a graph 2552. Although a single electrode is selected inthe user interface and used for ablation in the illustrated embodiment,certain embodiments provide for multiple electrodes selected and used atonce for ablation. Also, ablation may be interrupted while switchingbetween electrodes used for ablation. The switching between differentelectrodes for ablation may be implemented in any manner that allows forenergy used for ablation to be guided to different electrodes of themulti-pole synchronous pulmonary artery radiofrequency ablationcatheter, such as via digital or analog/solid state switching.

FIG. 25H is a screen shot 2580 of a user interface of the digitalablation controller 2500 presenting information on stored patientprofiles. The user interface indicates that there are two patientprofiles 2582, 2584 that may be selected. The patient profiles arepresented with a name 2586, patent identification number 2588 and time2590 of last access of the stored patient profile. The user interfacealso includes buttons 2592 for exporting the various patient profilesand an option button 2594 to delete a selected patient profile.

FIG. 26 is a schematic diagram illustrating a mechanical switchingsystem 2600 that may be implemented in the controller 2500 of FIGS.25A-25H or the controller 100 of FIGS. 15C-15D. The mechanical switchingsystem 2600 includes a source contact 2602, a mechanical switch 2604,electrode contacts 2606A-J, and a ground contact 2610. The sourcecontact 2602 may be connected with a source of RF energy at a levelsufficient for ablation. The electrode contacts 2606A-J may be eachconnected with a different electrode 2608A-J that may be used forablation. The ground contact 2610 may be connected to ground 2612. Theelectrodes 2608A-J may be located at the distal end of the catheter. Themechanical switch 2604 may be actuated as part of a dial or knob 2612that may be physically moved such that the mechanical switch 2604connects the source contact 2602 with a particular electrode contact2606A-J or the ground contact 2610. For example, the mechanical switch2604 may be actuated by being physically moved in a clockwise or acounter clockwise direction. In the illustrated embodiment, the switch2604 is positioned to connect the source contact 2602 to the electrodecontact 2606A.

FIG. 27 is a schematic diagram illustrating a solid state switchingsystem 2700 that may be implemented in the controller 2500 of FIGS.25A-25H or the controller 100 of FIGS. 15C-15D. In contrast with themechanical switching system 2600 of FIG. 26, the solid state switchingsystem 2700 is actuated without use of any physically moving parts. Thesolid state switching system 2700 may include the source contact 2602, aselector contact 2702 connected with a signal source, solid stateswitches 2704A-J, the electrode contacts 2606A-J, and ground 2612. Theelectrode contacts 2606A-J are each connected with the differentelectrodes 2608A-J that may be used for ablation. The source contact2602 may be connected with the source of RF energy at a level sufficientfor ablation. The solid state switching system may set the selectorcontact 2702 to a particular signal (such as to a particular voltagelevel) that causes a particular solid state switch 2704A-J to connectthe source contact 2602 with a particular electrode contact 2606A-J. Forexample, the solid state switching system may set the selector contact2702 to a voltage level which activates solid state switch 2704J toconnect the source contact 2602 with the electrode contact 2606J,thereby providing RF energy at a level sufficient for ablation to theelectrode associated with the electrode contact 2606J. Also, the othersolid state switches 2604A-I may maintain a connection between theirassociated electrode contacts 2606A-I and ground 2612 while the solidstate switch 2604J connects the source contact 2602 to the electrodecontact 2606J. The solid state switches may be implemented using anytype of solid state device, including MOSFETs, IGBTs, bipolartransistors, and thyristors.

FIG. 28 is a diagram illustrating a generic switching system 2800 thatmay be implemented in the controller 2500 of FIGS. 25A-25H or thecontroller 100 of FIGS. 15C-15D. The generic switching system 2800 mayimplement any type of switching system to connect the source contact2602 to a particular electrode contact 2606A-J. For example, the genericswitching system may be implemented using mechanical switches, solidstate switches, or a combination of mechanical and solid state switches.

As used herein, the term “animal” is intended to include human beingsand other animals such canines, other mammals, etc. As used herein, theterms “live”, “living”, “live animal” are intended to exclude methods ofeuthanasia, surgery performed on dead animals including dissection andautopsies, or other techniques for disposing of dead bodies.

While at least a plurality of different embodiments are disclosedherein, it should be appreciated that a vast number of variations exist.It should also be appreciated that the embodiments described herein arenot intended to limit the scope, applicability, or configuration of theclaimed subject matter in any way. Rather, the foregoing detaileddescription will provide those skilled in the art with a convenient roadmap for implementing the described embodiments. It should be understoodthat various changes can be made in the function and arrangement ofelements or steps without departing from the scope defined by theclaims, which includes known equivalents and foreseeable equivalents atthe time of filing this patent application.

1-61. (canceled)
 62. A controller, comprising: a housing comprising: aconnection port disposed along a surface of the housing, the connectionport configured to interface with a catheter comprising a firstelectrode of a first length, and a second electrode of a second lengthdifferent than the first length, a user interface disposed along thesurface of the housing, wherein the housing envelops an electronic datastore and a computing device; the user interface; the electronic datastore; and the computing device including one or more processors, thecomputing device in communication with the electronic data store, andthe user interface, the computing device configured to at least: receivea selection of the first electrode from the user interface, direct powerat a first power level sufficient for ablation using the first electrodeto the first electrode, receive a selection of the second electrode fromthe user interface, and direct power at a second power level sufficientfor ablation using the second electrode to the second electrode.
 63. Thecontroller of claim 62, wherein the computing device is configured todirect power to the first electrode and direct power to the secondelectrode at a same time.
 64. The controller of claim 62, wherein thecomputing device is configured to direct power to the first electrodeand direct power to the second electrode at different times.
 65. Thecontroller of claim 62, wherein the computing device is configured tointerrupt power directed to the first electrode and direct power to thesecond electrode after the power directed from the battery to the firstelectrode is interrupted.
 66. The controller of claim 62, wherein thecatheter comprises an annular ring shaped with an oval comprising amajor axis and a minor axis, wherein the major axis comprises a firstdiameter along the major axis longer than a second diameter along theminor axis, wherein the first electrode straddles the apex of the majoraxis.
 67. The controller of claim 62, further comprising a batteryconfigured to store power at the first power level sufficient forablation using the first electrode or the second power level sufficientfor ablation using the second electrode, wherein: the housing envelopsthe battery, and the computing device is in communication with thebattery and configured to: direct power from the battery at the firstpower level sufficient for ablation using the first electrode, anddirect power from the battery at the second power level sufficient forablation using the second electrode.
 68. The controller of claim 67,wherein the housing comprises a power connection port configured toreceive power at a level sufficient to charge the battery.
 69. Thecontroller of claim 68, wherein the computing device is configured todirect power from the battery to the first electrode after the batteryhas finished charging.
 70. The controller of claim 68, wherein thecomputing device is configured to direct power from the battery to thesecond electrode after the battery has finished charging.
 71. Thecontroller of claim 62, wherein the catheter comprises a first sensorconnected with the first electrode.
 72. The controller of claim 71,wherein the computing device is further configured to display on theuser interface first electrode ablation information captured by thefirst sensor while the computing device directs power to the firstelectrode.
 73. The controller of claim 62, wherein the cathetercomprises a first sensor connected with the first electrode and a secondsensor connected with the second electrode.
 74. The controller of claim73, wherein the computing device is further configured to display on theuser interface first electrode ablation information captured by thefirst sensor while the computing device directs power to the firstelectrode and second electrode ablation information captured by thesecond sensor while the computing device directs power to the secondelectrode.
 75. The controller of claim 74, wherein the second electrodeablation information is displayed on the user interface after thecomputing device stops directing power to the first electrode.
 76. Acomputer-implemented method comprising: under control of one morecomputing devices executing specific computer-executable instructions,receiving a selection of a first electrode on a user interface disposedacross a surface of a housing, the housing comprising a catheterconnection port disposed along a surface of the housing, the connectionport configured to interface with a catheter comprising a firstelectrode of a first length, and a second electrode of a second lengthdifferent than the first length, the housing enveloping an electronicdata store and the one or more computing devices executing specificcomputer-executable instructions; directing power at a first power levelsufficient for ablation using the first electrode to the firstelectrode; receiving a selection of the second electrode from the userinterface; and switching from directing power to the first electrode todirecting power at a second power level sufficient for ablation usingthe second electrode to the second electrode.
 77. The method of claim76, wherein the switching is performed using a mechanical switch thatcomprises at least one moving part.
 78. The method of claim 77, whereinthe user interface is a rotatable knob.
 79. The method of claim 76,wherein the switching is performed using a switching system comprising:a mechanical switch that comprises at least one moving part, and a solidstate switch that comprises no moving parts.
 80. A computer-readable,non-transitory storage medium storing computer executable instructionsthat, when executed by one or more computer systems, configure the oneor more computer systems to perform operations comprising: receiving aselection of a first electrode from a user interface presented on anelectronic display disposed across a surface of a housing, the housingcomprising a catheter connection port disposed along a surface of thehousing, the connection port configured to interface with a cathetercomprising a first electrode of a first length, and a second electrodeof a second length different than the first length, the housingenveloping an electronic data store and the one or more computersystems; directing power at a first power level sufficient for ablationusing the first electrode to the first electrode; receiving a selectionof the second electrode from the user interface, and switching fromdirecting power to the first electrode to directing power at a secondpower level sufficient for ablation using the second electrode to thesecond electrode.
 81. The computer-readable, non-transitory storagemedium of claim 80, wherein the switching is performed by controlling asolid state switch that comprises no moving parts.